That's an important question, but a different one. Surely we could preserve the collected works of Steig Larsson or J.K. Rowling without asking every reader on Earth to buy and retain a physical copy.

(If nothing else, if in three hundred years the works of Steig Larsson are somehow lost, our descendents can just have the archaeologists dig down a few feet, where they will discover a stratum consisting of nothing but remaindered Steig Larsson paperbacks.)

More seriously: It's likely that books will continue to have print runs, but the question is the size of those print runs. You can preserve a novel by having twenty librarians in twenty countries run off twenty printed copies and stash each of them in a storage vault. But that market won't support a physical infrastructure of printed-book sellers.

I see this worry about the historical record disappearing, and think it is misplaced. We have plenty of knowledge of civilization from hundreds of years ago, despite a near total lack of written records at the time.

And frankly, it's probably a good thing that a lot of records disappear. How many books about WW2 can you read? Is it remotely useful to keep all the accounting records of every company for future generations? There's a lot of angst about half of the silent movies having disappeared, but let's be honest - most of the silent movies were trash churned out for a quick buck.