Publishers print massive amounts of books in the hopes that they will sell. The majority of these sit in warehouses and never see daylight, and are then recycled. Some make it out to stores, and then get returned to the publisher, and recycled.
We have a viable alternative to print books, why don't we just find a way to improve those to the point that people don't want the printed material anymore.
I think the opportunity, truly, is in discovery. I still, sadly, go into bookstores to find what I want to buy, and then go buy the digital version. I wish there was something as good as browsing a bookstore, but there isn't. It would be great if I could go to the bookstore, if I download a book from within their location, they get a cut.