Comment: Looks a bit like Safari (Score 1) 70
Subscription services for books like Safari Books Online http://my.safaribooksonline.com/9781449309473 already "loans" books with a model like this. They pay out from a pool based on the number of times a book is selected from their library. Of course a single use isn't going to pay out as much as a purchase, but the alternative is for a Safari-like subscription library to buy a single copy, or as many copies as would be used simultaneously, and do license management. And that opens the whole DRM can of worms.
An open-ended revenue model can be advantageous to authors of frequently-read books.