"The most important thing to observe is that books don't just compete against books. Books compete against people reading blogs and news articles and playing video games and watching TV and going to see movies.
Books are the competitive set for leisure time. It takes many hours to read a book. It’s a big commitment. If you narrow your field of view and only think about books competing against books, you make really bad decisions. What we really have to do, if we want a healthy culture of long-form reading, is to make books more accessible.
Part of that is making them less expensive. Books, in my view, are too expensive. Thirty dollars for a book is too expensive. If I'm only competing against other $30 books, then you don’t get there. If you realize that you're really competing against Candy Crush and everything else, then you start to say, “Gosh, maybe we should really work on reducing friction on long-form reading." That’s what Kindle has been about from the very beginning."
That's from a very good interview from Business Insider.