At the same time, I think books create a sort of network in the reader's mind, with one book reinforcing another. Some books form relationships. Other books stand in opposition. No two writers or readers have the same pattern of interaction.
The crazy thing is that when we go to somebody's house, what's better than looking at their bookshelves? Nobody's ever going to say, "Can I see the index to your Kindle?" It's so depressing and so unsexy. Sure, it's there, but nobody is going to get excited by that.