I forgot what football analyst said it, but he said that pro boxers are not athletes. Do you agree?

Boxing is the hardest/toughest mainstream sport in the world. You need to be some sort of athlete to be a boxer. I know there are some guys like Butter Bean who aren't athletes but still. I would love to see any other athlete get in the ring with Ali in his prime or Sugar Ray Robinson. They would be out of breath by the 4th round when these guys are just getting started. They condition like Animals.