Rationing works when people can make do with a small amount of something despite preferring a larger amount. In particular, food rationing was not about alternatives, but simply about restricting everyone's diet so that a limited food supply would be consumed more slowly without starving anyone.
One of the most difficult shortages during WW2 was rubber, because there was no (known, at the time) comparable alternative.
With GPUs, rationing would have the same effect as a lottery -- you either get to run AI, or you don't.