Since we have seen that the power necessary for lift is proportional to one over the length of the wing, a wing of infinite span does not require power for lift
An infinite span - It's an absurdity on the face of it, right?
Simply postulating a mathematical asymtotic extrapolation doesn't mean we have to build the damn thing.
Matter of fact, if we build a wing with slightly over a 40 million meter span, the left tip will meet the right tip, there will be no tip vortices, and it can float at zero IAS.
