I do not believe that all books will or should migrate onto screens: as Douglas Adams once pointed out to me, more than 20 years before the Kindle showed up, a physical book is like a shark. Sharks are old: there were sharks in the ocean before the dinosaurs. And the reason there are still sharks around is that sharks are better at being sharks than anything else is. Physical books are tough, hard to destroy, bath-resistant, solar-operated, feel good in your hand: they are good at being books, and there will always be a place for them.
Neil Gaiman in a talk about libraries