Relying on literary adaptations is a symptom of Hollywood's decline from the golden age of The Maltese Falcon (1941 remake of a 1931 adaptation of a 1930 novel), Gone with the Wind (from the bestseller by Margaret Mitchell) and The Adventures of Robin Hood (way more than a hundred years old in 1938)?
The reason most Hollywood material is adapted material, is that a movie is a hell of an expensive place to try out new ideas. A book costs little to write, and takes one person to write it. And there are lots of them, succeeding, or failing, on the strength of their ideas, writing and storytelling. Cinema has never been the place to run a lot of flags up the pole and see which one the public salutes.
The reason most Hollywood material is adapted material, is that a movie is a hell of an expensive place to try out new ideas. A book costs little to write, and takes one person to write it. And there are lots of them, succeeding, or failing, on the strength of their ideas, writing and storytelling. Cinema has never been the place to run a lot of flags up the pole and see which one the public salutes.