The Big Sky is one of my favourite western novels - because it goes against all the "Western" rules. It's main character is vicious, angry and dangerous. In the first chapter, he tries to kill his own father (a fate the old creep richly deserves). If he's insulted,he pulls out a knife. When someone whips him, he comes back later planning a killing. People die throughout the book,they get scalped and VD and smallpox - kind of the way people did in the frontier.
So what does Hollywood do? Make the lead the supporting character, the sidekick the lead (& make him Kirk Douglas - nice & non-threatening). Start the movie several chapters in, so you don't see Dada cop it. Oh, and the boatload of characters waving at the Indians at the end? Halfway through the book, those same Indians wiped them out. 'Nuff said. If you decide to make a movie of a book, why change it?
So what does Hollywood do? Make the lead the supporting character, the sidekick the lead (& make him Kirk Douglas - nice & non-threatening). Start the movie several chapters in, so you don't see Dada cop it. Oh, and the boatload of characters waving at the Indians at the end? Halfway through the book, those same Indians wiped them out. 'Nuff said. If you decide to make a movie of a book, why change it?