The two parallel arches in the Godfather trilogy follow the stories of Vito and Michael Corleone, the main motivation for both of them being to protect their family.
Vito succeeds, while his son, Michael can see the family gradually being undone.
What exactly did he do "wrong"?
He is smarter than most (maybe all) other characters in the movie, has an accurate sense of what other people might be plotting, and has a deep understanding of how everything works. From all the sons of Vito Corleone, he was by far the most competent. Sonny was too hot-headed, Fredo was too much of a coward. Is there a canonical answer why he fails?
I would guess that either
- the times and the system are changing, leading inevitably to the fall of the traditional Prohibition-style "business",
- or that he was doing "too well", so the competing families saw his family as a great threat to the balance and so they invested a lot of combined effort to destroy him
going so far as to manage to turn his own brother, Fredo, into a traitor
Is there a canonical (or at least very highly suggested) answer to this question? I understand that this (trying to protect the family and failing) is a major topic in the movie, but is it addressed why he manages it much worse than his father did, despite not making any obvious mistakes?