“For my grandchildren, the idea that reading is something you do by yourself will seem arcane,” he says. “Why would you want to read by yourself if you can have access to the ideas of others you know and trust, or to the insights of people from all over the world?”
Though what's authored in a book might not be from anyone we know and trust (in itself not a "bad" thing) it's quite likely still a body of (possibly collective) insight already—perhaps even from someone(s) in less-local parts of the world.
Maybe I missed the point, but it felt like the quote was missing that a book is already a view into others' ideas and insights.
That said, even if printed books are to fall out of favor with the majority of literate people, it could still be a good idea to maintain physical libraries of works that many would find essential in the (perhaps unlikely) case that digital records fail or become inconvenient to access.