> Basically, physical books wear out with use, ebooks don't, so there's a built-in mechanism for revenue recurrence that happens with print books but not ebooks.
While physical books might indeed wear out, I think they wear out way slower than what current library e-book licenses might suggest (apparently two years or 26 lends seems to be popular in the US? – my library has tons of books older than two years, and back from when they used to stamp the return date in the back, quite a few books had hit 26 lends without falling apart yet).
Also, physical books can be rebound/repaired. The binding is usually the point of failure, and even smaller libraries often have rebinding equipment. I worked in libraries for over a decade and I could probably count on one hand how many books (as opposed to CDs/DVDs/other materials) that were weeded due to condition versus because they simply weren't used or contained out of date/wrong information.