Robert Towne's script ends with Evelyn dying from police bullets before Cross can make her divulge Katherine's hiding place. Polanski changed the ending so that Katherine was present during the shooting; Cross spirited her away, unhindered by the police, and evil triumphed. Towne considered the Polanski ending to be a contrivance and a desecration of his work. I incline to Towne's point of view--what do you think?
From the 1990s till today, Towne has admitted he was wrong.
While on some level the ending represents a big theme regarding injustice, the ending is really about the culmination of Jake Gittes' continuous mistakes.
You just can't reward an incompetent "hero" the way Robert Towne wanted to.
That might work in the 1940s or 1950s where the detective always resolves matters to the relief of audiences during those times but not for a film illustrative of modern society.
But above all, you'd clearly have to have a different score with Towne's ending.
Even if the woman did not die at the end, the farmers in the Valley will still lose their land to the Land baron's development plans. The "hero" does not win and neither do the people he was representing .
Actually, in Towne's original conception of the story, Evelyn kills her father and Katherine is saved. A later draft version of the script already reflects Polanski's contention that Evelyn must die. This is what Towne said in a 1975 interview in American Film Magazine (he has since conceded that Polanski was right—see his interview on the DVD extras):
"Originally, I had Evelyn kill her father. Gittes tried to stop her but was too late. But he did succeed in getting her daughter out of the country. So the ending was bittersweet in that one person at least—the child—wasn't tainted. The one thing the woman had been trying to do—the purest motive in the whole film—was to protect her daughter. When she carried out this motive by killing her father, she was acting out of motherly love. You knew she was going to stand trial, that she wouldn't tell why she did it, and that she would be punished. But the larger crime—the crime against the whole community—would go unpunished. And, in a sense, that was the point. There are some crimes for which you get punished, and there are some crimes that our society isn't equipped to punish, and so we reward the criminals. In this case, greedy men displaced a whole community and took the land. So there's really nothing to do but put their names on plaques and make them pillars of the community. It was this balance I was looking for."
Don't forget that aspects of the (greatest ever) score would have to be different with Towne's ending.
While the whole score is melancholy, there are two cues that are blatant in foreboding that would be pointless with Towne's ending.
I'd also add that with only those two cues alone, Goldsmith creates as much foreboding as the entirety of Miklos Rosza's Double Indemnity and that is a spectacular feat.
I don't understand your need to assert your opinion of the score in all of your posts, it would better to resist that urge if you don't want people to ignore you. Perhaps you could start a thread for it.
But to answer the OP's question, for me the deep impact that the film achieves through Polanski's dark vision would have been diminished with Towne's "happy" ending.
First of all, the score is arguably the single greatest aspect of the film. Robert Towne, Robert Evans, and Sam O'steen have all suggested as much.
It also isn't my opinion that there are parts of two cues that while very brief, are blatant in foreboding, which means that if you bring up Towne's ending, then I would have to accurately point out that aspects of the score would have to be changed. I'm not going to "play pretend" as if that score was there at the beginning or even resembles the scores of classic film noir, which it doesn't.
Lastly, the deep impact of the film, achieved through Jerry Goldsmith's sparse scoring, as well as Polanski's direction, would have been diminished by the immensely inferior Roman Polanski/Phillip Lambro score just as much as Robert Towne's equally inferior ending.
But in all honesty, the Polanski/Lambro score is probably worse than Towne's terrible ending which I think says a lot.
You are free to express your opinions about the score, of course, I just don't think it has much to do with whether or not Polanski desecrated Towne's work.
I think we're pretty much in agreement with regards to Robert Towne's very terrible ending.
At the end of the day the main character is still Jake Gittes. No matter how vast or impressive the themes are regarding corruption, this film centers around Jake Gittes.
And arguably the most important characteristic of Jake Gittes is that he is unconstructive in literally every single scene in the film. When you take into account Towne's ending, the fact that Gittes is in every scene of the film, the fact that Gittes has no impact on the corruption at any time during the film, and the fact that Gittes is deeply mistake-prone, Towne's ending is exceedingly out of place.
It's also true, however, like many others have suggested, that Towne's "happy ending" for a film illustrating how corruption is ruining the city in multiple ways is also out of place.