One reason is defensive, against lawsuits. When you license a book or ‘life rights’, you get a defense against someone saying ‘you stole my story’. (See for example Terminator getting successfully extorted by Harlan Ellison.) So they may actually go around and buy the movie rights to things that everyone knows is unrelated just to preemptively buy out any possible lawsuit grounds. While this may be ‘pennies from heaven’ for many writers, it has at least once had rather perverse consequences for one of my favorite writers, R. A. Lafferty, posthumously in creating a tragedy of the anticommons: https://ralafferty.tumblr.com/post/55382042501/49-the-six-fingers-of-time AFAIK, this also explains the bizarre practice of buying ‘movie rights’ for nonfiction reporting; for example, one of the Silk Road 1 movies was based on ‘licensing’ some articles from Wired. Or of ‘licensing’ public domain characters like Sherlock Holmes when you want to make a movie about Sherlock Holmes and are worried about an estate suing you over elements like ‘Holmes showing human emotions’ which are supposedly derived from still-copyrighted stories.
One reason is defensive, against lawsuits. When you license a book or ‘life rights’, you get a defense against someone saying ‘you stole my story’. (See for example Terminator getting successfully extorted by Harlan Ellison.) So they may actually go around and buy the movie rights to things that everyone knows is unrelated just to preemptively buy out any possible lawsuit grounds. While this may be ‘pennies from heaven’ for many writers, it has at least once had rather perverse consequences for one of my favorite writers, R. A. Lafferty, posthumously in creating a tragedy of the anticommons: https://ralafferty.tumblr.com/post/55382042501/49-the-six-fingers-of-time AFAIK, this also explains the bizarre practice of buying ‘movie rights’ for nonfiction reporting; for example, one of the Silk Road 1 movies was based on ‘licensing’ some articles from Wired. Or of ‘licensing’ public domain characters like Sherlock Holmes when you want to make a movie about Sherlock Holmes and are worried about an estate suing you over elements like ‘Holmes showing human emotions’ which are supposedly derived from still-copyrighted stories.