One of the main differences between printed books and books and articles that we find online is how we store them. Sure, there must be some people who read articles from the screen, and only bookmark them for possible future reference, but there are probably people who put ketchup on their ice cream as well. Normal people send things to the printer and comfortably sit down with a stack of A4 pages in their hands and read. Then, instead of putting the article on their shelves, they store it away in their filing cabinets. This is, of course, less impressive than having books on the shelf (we've already alluded to that) but it does save a lot of shelf space and is much less messy. On the other hand, lots of books on the shelf still impresses people. Normal people don't open other people's filing cabinets in order to see what's inside them, whether or not the contents are impressive.
But the clutter on my shelves isn't the issue here. It's whether worthwhile academic materials are going to continue to be freely available via the web. There are numerous advantages to free availability. As consumers we love it, and my guess is that authors like the idea of their intellectual produce "out there" for everyone to see. But somewhere along the line the university is going to ask why it's not making money off all of this free exchange of ideas.