The real damage from piracy comes from distribution, rather than consumption. Lending might do a small amount of damage, but as long as the inventory publishers have has been paid for somehow, they don't really care. They would care if libraries started running printing presses in the back and gave away extra copies for free, which were indistinguishable from the original, which is essentially the piracy model.

IANAL but I'm honestly not even certain that the piracy service you describe would actually be illegal, or at least that it couldn't be done legally.