Many of the older books are not digitised and probably never will be. And reading poorly scanned PDFs on a computer screen sucks. Some of the new books are released in paper only as well. Non-tech books don't get more or less up to date. In fact, paper books are great that they can't be easily edited.

Of course "build it and they'll come" doesn't work. But if we could get more people to come to libraries, it'd be awesome in all sorts of ways. And without building it, nobody will even have a chance to come.