The copying only exists on a technical level because digital stuff is weird. Only one copy is usable at a time.
So either IA is guilty of copying because of a technicality, or normal libraries are only allowed because of a technicality/exception. (Because normal libraries fail the transformation test, they fail the amount copied test, they fail the expressive nature test, and they fail the market impact test.)
I want to believe the former is correct. Either way I believe there should be a way for IA to access that same "this isn't considered copying" territory somehow.
The only difference is whether technically copying happens, because controlled digital lending has the same results as a system that involves no copying. It doesn't have the common definition of copying where two people can access two copies at the same time.
If IA came first, and libraries came second, would we refer to libraries as having a technicality/exception that lets them be legal?
Though I suspect that if libraries were invented right now they'd be declared illegal.