It seems like all Vietnam war movies are either about individual characters in some abstract Vietnam war setting or individual battles/incidents. There are no movies that cover the history and progression of the war itself from start to finish that I can think of. Even documentary films, there just doesn't seem to be much interest in what happened in the war. This seems to be unique to Vietnam. Why is this?
Public sentiment against the Vietnam War meant that it was difficult to show the war in a satisfactory light, especially given that it ended in a costly American defeat. Hollywood had more financial success with focusing on a sympathetic individual or group and leaving the unsympathetic war as a background.
Michael Paris, emeritus professor of modern history at University of Central Lancashire, talked about this at length in his article "The American Film Industry & Vietnam", published for the magazine History Today. The whole article is an interesting read, so I'll summarize some of his points.
While the war was going on, it became unpopular to sympathetically show the war
Obviously, you can't create a movie about the entire Vietnam war it before it is concluded. But it's important to realize the film landscape as it led up to the end of the war. Paris points out that anti-war sentiment was so high that it became a contentious subject for the populace.
By 1968, it was no longer possible for the film industry to deal with the war in this straightforward and traditional manner. It had become the most divisive event in American history since the Civil War. The Tet Offensive had convinced many that the war could not be won, thus strengthening the anti-war movement which was becoming so widespread it could no longer be ignored. How was the film industry to present the war when the President had to appear on national television to appeal for consensus and when even the Government was divided? Hollywood could not even rely on the relatively non-political 'action' war film, for public feeling was too incensed.
Additionally, just showing footage of the war was no longer viable, as it was in World War II and to a lesser extent the Korean War, due to television becoming increasingly popular.
Moreover, television, with its live coverage of the battlefield, was usurping the cinema's role of presenting the image of the war to the public.
Studios are ultimately profit-driven, and most common moviegoers were those most likely to be unsympathetic to the war
Film makers, conscious of the need for financial success, have always had to play safe and reflect rather than lead public opinion. The difficult years after 1960, when audiences declined and studios closed down, made this even more necessary. A Newsweek survey, published in 1970, revealed that 62 per cent of regular film-goers were aged under thirty-years; precisely the age group that had been or would be going to Vietnam, and the group most active in the peace movement. Understandably, this audience wanted a cinema which was relevant and reflected their own doubts about the war.
While initially Hollywood chose not to create films about Vietnam, it ultimately became such a part of American life that it was necessary to do so, and they thus had to match anti-war sentiment.
Between 1968-73 the war in Vietnam was so much a part of American life it could not be ignored, so Hollywood somewhat unhappily began to pander to this new, and anti-establishment audience. It was unnatural, however, for such an inherently conservative industry to be dissident and subsequently most pictures dealing with the war emerge as politically ambiguous.
Given this, two alternative genres were created to address the film indirectly
War coverage is a background intruding in on a contemporary drama.
One device adopted by some directors was to use the endless radio and television coverage of the war as a background for contemporary drama. The Roger Corman/Peter Fonda narrative of doomed youth, Wild Angels (1966) used this technique as did Petulia (1968). But this was merely an acknowledgement of the war and its intrusion into every aspect of American life.
Students against the war
Students and the anti-war movement were also the focus of The Strawberry Statement, Getting Straight and Summertree, all made in 1970. […] The 'youth against the war' feature had little financial or critical success but it remained the only way in which Hollywood was prepared to deal with the war until after the withdrawal of American troops from Vietnam in 1973.
After the war, "veteran" films became popular focusing on individuals
But even after 1973, the war's legacy of bitterness still created difficulties for film makers and it was not until the late 1970s that they would face the war head on. Instead the industry began to produce a type of feature full of anti-war sentiments, but glorifying the individual soldier – the 'veteran' picture. […]
But this type of film became a staple product for the industry when dealing with the Vietnam War in the mid-1970s. In the veteran film revenge usually provides the motive for the drama; yet only one, Good Guys Wear Black (1977), deals with revenge for something which has happened in Vietnam. […]
The critical success of Taxi Driver [(1976)] inevitably drew many imitations; cheaply-made, burdened with gratuitous violence, they have little artistic or social interest. Only Sylvester Stallone's First Blood (1982) offers an interesting variation of the theme.
Paris argues that this film was popular because it provided a sympathetic protagonist, but was unsympathetic towards the US government.
Here we are confronted most forcefully by the ambiguities of the veteran feature. The film condemns the army for creating a killing machine like Rambo but continually places him in situations where the audience are expected to admire his fighting skills. Significantly, the David Morrell novel, upon which the film was based, has Rambo shot down at the end like the mad dog he has become. The film reflects the changing attitude to the war in America, however, for at the end Rambo surrenders, confessing his anger is really directed at those who prevented the 'total war' tactics in Vietnam for which he had been trained and which could have won the war.
And yes, he did say "the David Morrell novel, upon which the film was based". Believe it or not, Rambo is a book adaptation.
Some anti-war producers had a difficult time securing funding for films about the Vietnam War
Jane Fonda had a successful career in documentaries, but had to create her own studio in order to make the film she wanted to about a veteran of the Vietnam War.
[Jane] Fonda had been a leading figure in the anti-war movement since her visit to Hanoi in 1972. There she had broadcast anti-war statements and made her opposition to the war public. This led to harrassment from the Federal Bureau of Investigation and the condemnation of American hawks. Even five years after the war ended, her proven box-office appeal was not enough to secure backing from a major studio for Coming Home [(1978)].
When the studios began to show the War directly, it continued the same pattern
1977-78 saw a major revival of interest in the war by the film industry. Perhaps sufficient time had elapsed for some of the bitterness to fade; perhaps it was the news that Francis Ford Coppola, wonder-boy of the new Hollywood, was producing a multi-million dollar epic about the war? But for whatever reason, the studios began to show interest and to view the war in a more direct way.
He provides several examples such as The Boys in Company C (1977), Go Tell The Spartans (1978), The Deer Hunter (1978), and Francis Copola's Apocalypse Now (1979), all of which dealt with flawed yet sympathetic soldiers in an unsympathetic war, often with morally bankrupt superior officers.
Talking about the whole Vietnam War means talking about the costly American defeat, and unsavory aspects of American involvement
Paris argues that for some time, the film industry seemed unable to address the ultimate end of the Vietnam War and the defeat to Americans.
The American film industry, then, can hardly be accused of ignoring the Vietnam War. But what it has ignored are some of the more unpleasant aspects of that conflict. No film has yet presented any real justification for Americans going to South-East Asia other than in the most vague terms such as to combat 'Communist aggression' or to fulfil 'treaty obligations'. No American feature has dealt with the end of the war, the withdrawal of American troops in 1973 or the subsequent fall of Saigon in 1975. It appears that Americans have yet to come to terms with defeat and it seems fashionable to soften the truth with phrases like 'the war that nobody won'. So too, by emphasising the corruption of the South, films appear to be suggesting that America withdrew because she could no longer support an unworthy ally. All of which diverts attention from the harsh reality – that America suffered a costly military defeat.
The article was written in 1987, but to my knowledge, this is still generally true. In fact, the only films I could find that explored the fall of Saigon was the obscure documentary The Fall of Saigon (1995) and the American Experience episode Last Days in Vietnam (2014). Heck, a film adaptation of the long-running broadway show Miss Saigon (which again shows sympathetic characters with the background of the unsympathetic Vietnam War, and features the fall of Saigon) is in development hell.
Also, no films to my knowledge have ever addressed the unsavory aspects of American involvement, such as de-foliation or chemical weapons.
Other aspects of the war have also been ignored in the cinema's view of events. There has been no mention of the de-foliation programmes or reference to other chemical weapons; nor of the massive bombing campaigns against North Vietnam or Laos. The features invariably include a few token black soldiers in the cast, but one feature of the real war was the extremely high proportion of black Americans assigned to combat duty. Where are they in the industry's simulation of reality?
In the 1980s, conservatism in Hollywood led to films being made that were more defensive of the Vietnam War
With a more defensive take on the Vietnam War, it was unlikely that Hollywood would address the conflict in unpatriotic terms.
Since the beginning of the present decade [the 1980s], then, mainstream Hollywood has begun to reflect the growing conservatism of American politics. As far as the Vietnam War is concerned, this has meant feature films which are more openly defensive about American involvement. The most recent features have dealt with commando raids into present-day Vietnam to release prisoners-of-war still held by the communists. Uncommon Valor (1983), Missing in Action (1984) and the phenomenally successful Rambo have all shown that the communists can be beaten and have attempted to restore military self- respect. Rambo, interestingly, was endorsed by President Reagan who, only half-jokingly, advocated Rambo-style action to release hostages. The sociologist Norman Chinchilla has suggested that Rambo is a revenge object, not only against the Vietnamese, but on an American government which denied victory to American arms. The film industry's interpretations of the Vietnam experience have had little impact on public thinking about the war, but what the cinema has done has been to reflect, albeit sometimes dishonestly, America's changing attitudes to that conflict. Now, under the present administration [of Ronald Reagan], Hollywood's political perspective has turned full circle and is now, once again, the voice of patriotism.
A few notes about afterwards
A quick scan of Wikipedia's article on Vietnam War in film shows that pretty much every film since the article was written follows this pattern: focus on an individual who is sympathetic and show the war itself either defensively or as an unsympathetic background. It seems Hollywood has found this to be a more profitable moneymaking strategy than showing the conflict in full, especially the end of the war.
What about non-Hollywood and non-US movies about Vietnam?
But mostly the Hanoi-based industry focused on documenting the Vietnam War. Between 1965 and 1973, 463 newsreels, 307 documentaries and 141 scientific films were produced, in contrast to just 36 feature films and 27 cartoons.
Films during this period include the documentaries Du kích Củ Chi (Củ Chi Guerillas) in 1967 and Lũy thép Vĩnh Linh (Vĩnh Linh Steel Rampart) in 1970, which included footage from battles. Other films, such as Đường ra phía trước (The Road to the Front) in 1969 and Những người săn thú trên núi Dak-sao (Hunters on Dak-sao Mountain) in 1971 were docudramas."
Note the conflict in Vietnam stretched from the 1940s through to the 1970s, not just the years when the US was involved.