Google Books Subscription?

So. . .if libraries and universities can buy subscriptions to the full archive, how far away is K-12? If k-12 can buy subscriptions, what happens if those books are available on demand versioned for a particular classroom at a particular time?

US: Google Books Drives Visits to Book Retailers:

"Among other things, the settlement allows universities and libraries to buy a subscription to the entire collection of scanned books in Google's archives. Last week, 22% of visits from Google Book Search went to an Education website, with Worldcat (a website that allows users to search library catalogs) the #3 downstream website overall and the #1 Education website."