I've always thought that if they allow ereaders to share books with other ereaders, but only via bluetooth, then that would pretty much solve everyones problem.
You can still share books with close friends and family that you know, but not with everyone on facebook.
Library lending could be done the same way as well, so you have to physically go into the library (like you always had to with pbooks).
My library is only about 50 yards from me and I still can't be bothered going there to see if they happen to have a book I want, easier to order it online, although with ebook lending the process is about the same effort as buying the book so more people will do it (I can see why publishers are worried about libraries in a digital world)