Here's a prediction. By 2020, the majority—perhaps even great majority— of books published in the U.S. won't ever be printed. Instead, they'll be automatically downloaded onto your reading device, which will probably double as your phone or personal computer, or both. Sure, you'll be able to get a hard copy if you want one, but that won't amount to much of a percentage. As a result, bookstores (if one can call them that) will empty of books, except for beautiful or heavily illustrated editions that will be at once collectors' items and objets d'arts.
And that's just how it should be. For five hundred years, the bound book has been a very robust deliverer of knowledge and information; but apart from the need to keep a few printed copies of each new book in existence just in case the entire planet's electronic system goes up in smoke, there is no particular need for most stuff to be printed. Just like CD sales are collapsing in the face of downloadable music, and DVD sales are going to fall as more and more people download video or stream it on-demand, book sales are going to fall as more content migrates to the online realm.
Again, this is an opportunity—although one that poses particular challenges for the book-publishing industry. Technology exists that allows publishing conglomerates that have digitized all of their content to combine it in innumerable ways. So, for instance, professors looking to provide their students with one book for the entire course that they're teaching, can literally custom-publish a title, made up of chapters from different books. Each chapter is priced and agglomerated in a standardized format until you've chosen all the texts. Then the copies required for the course are printed, and shipped out to the university. No returns, no need for piles of books to be purchased.
As far as we know, such a process can only exist within a publishing house: i.e., all of the content has to come from one publisher. But what if every chapter of an anthology, every short story, and every poem from every publisher were provided with its own ISBN (International Standard Book Number) and you weren't restricted to the same publisher? Then you could walk into the bookstore with the Espresso Book Machine and, say, compose a book of poems about cats from as many sources as you could find on a computer in the store, print one copy with its own unique dedication, and send it to the dedicatee. Authors would get a royalty for each story or poem rather than the entire collection; publishers would get more money from each of their chapters; people would get to be publishers for themselves; no book would be wasted. All in all, it's a good idea; and it's coming to a bookstore near you . . . soon.