At risk of "+1, yes, this," I was naively but genuinely surprised at how valuable library sales can be to books when I was researching that a couple years ago. For indie/small press, even a few hundred extra copies sold could be a substantial revenue bump -- and only a small fraction of libraries in the country buying just one copy of a book could do it.

(Also, I'm pretty sure publishers know this, and I don't think anyone of them have made serious arguments against libraries. It's digital media and its zero-cost reproduction that gives everyone fits.)

To pile on — think of the Amazon Kindle business model. You often pay more for instant gratification.

Even for popular books, it drives demand. You can wait 8 weeks to read the latest James Patterson, or buy it now. But would you buy the previous books in the series @ $20/ea?