Physical books will go away eventually because they won’t be economically viable to print in smaller numbers. Economically disadvantaged communities, without the “cushion” of advanced libraries with Internet Kiosks, public meeting spaces and other rich-folk goodies will be faced with less books, and eventually a realization that they’re maintaining an increasingly empty building. It may take a long time, but it will happen. And those “poor” libraries will close, while the “rich” ones thrive and diversify.
The public library is built around the book-lending model, and only luxury-home communities will want to justify public libraries on the scale we knew them in the 20th century, as a kind of trompe l’oeil to underscore their cultural creds. The other communities? They will fund police, fire, and the town square. Those humongous edifices filled largely with paper-based anachronisms may not be torn down anytime soon (though I’m sure ebook providers lick their chops over the idea of monopolistic control of consumption), but the service providers–we library workers–will be reduced to skeleton crews.