If I bought every book that interested me, I would have two problems. First, I would be totally broke. And second, I would have no more room in my apartment and would have to build a new house out of the books.
So, I am a heavy user of my local library. Plus, most books, especially fiction, I am never going to read again so it doesn’t make a lot of sense to purchase them. I do collect fairy tale collections and books about elephants but otherwise I really don’t need to own all the books I want to read.