What you need to remember is that in financial negotiation, the accounting department will never overtly declare that they are pursuing 'Hollywood Accounting', it is often something instigated through people being misled.
The wording/circumstances are often rephrased to evade detection: I believe 'Net Point Profit' was the circulating terminology for a long time, but has since fallen out of style as people have becomes immediately aware of its real definition.
David Prowse was a famous example of this, the man who 'played' Darth Vader...
After seeing how lucrative Sir Alec Guiness' net-point deal was, he signed on for a similar payment. What Prowse failed to realize however, was that Guiness' deal included the merchandising wing of Lucasfilm, not just the Movie itself. This resulted in Prowse still not being paid to this day, whilst Alec Guiness' estate continues to receive residuals.
In the case of Actors/talent, they often have little choice in the matter: if they want a part in the movie, they'll get what their given, and hope that the finance department is fair in the execution of debt owed.
Although not 'Hollywood Accounting', Jonah Hill is a recent example of this 'desperation' to be in a movie, taking only $60,000 for The Wolf of Wall Street, because it was the only way he could get Scorcese's people to agree to his involvement. That's a mainstream, Oscar nominated actor taking a financial hit to secure his role, so sometimes Actors will just take what they can.
Many 'in-house' department actually benefit from 'Rolling Profits', so if they are in on it, it makes sense to go along with the scam.
A good way to keep a movie out of profit is to keep going back and paying different departments for work 'owed', and delivering bonus' upon bonus'. If you've worked on the film, and are 'in on it' (and willing to co-operate), if the film is successful there's a good chance you'll receive some kind of surprise 'bonus' (who's real purpose is to stop the film having to commence net-point payouts).
As you've pointed out, there perhaps should be some kind of 'United We Stand' front against this kind of behavior, but unfortunately there are too many people complicit in its process, and the old system of 'Unions' was broken apart by the rise of the New Hollywood in 1969, so the only formidable force left in Hollywood is the SAG & WGA: which are themselves complicit in this process.
Unfortunately, Hollywood Accounting is borne out of two factors: Greed and Ignorance.
Until they are eradicated, its likely the practice will continue...
