If Hollywood buys your book, it's great.
True. Unfortunately, it seldom happens.
What happens more frequently is that Hollywood options the book, but never actually buys the rights and produces a movie. Even that small paycheck is welcome. It's a safe bet that many novelists in this group had their works optioned.
Only 3 saw the films produced, and in every case it had a big effect on their careers. Randall and Rebeta-Burditt's first novels became films and both subsequently wrote more television scripts than books. Lowry, having had a non-fiction book adapted for television, has since written more non-fiction than fiction.
Brooks and Chesbro wrote movie tie-in books. One of Brooks's topped the bestseller list.
In this group, we find no examples of a movie adaptation making an author's books more popular. No film has been based on the works of the most prolific authors, Hall, Swigart, Jackson, Chesbro, or--most surprisingly--Brooks.