A library doesn't need to "buy in bulk". All it needs is a willing and able group of people who donate used books, or who are willing to purchase services from the library (making copies, use of classes held there, binding, lamination, etc. can often be had from the library at cheaper cost than an office supply store).
Very few libraries, even now, buy brand spanking new volumes for their shelves. It would be an insane expense. Private citizens also donate new books, as evidenced by several drives on this forum to purchase and donate copies of Dr. Paul's or others' books to the local library.
I don't believe books are outdated, personally. I love them, and I would not trade them for some ridiculous .pdf. I read .pdf documents all day at work. A book is entirely different, and illustrations that go along with classics get a bit lost in translation when they're crisped up and incorporated into the e-document. There are still quite a number of bibliophiles out there. Audiobooks do nothing for me... it's like watching the movie version of a book. You are getting someone else's interpretation of the author's point of view. I prefer to do the interpretations myself. It's one of few genuine escapes left in the world.