I agree to an extent but you have to have a bit of a chin too. And stamina. 12 rounds is a long time to go against a big puncher and avoid a big bomb but it's a long time to keep your own glass jaw out of harm's way and a long time to go when you're knackered and it seems so many of history's big punchers lacked one or the other.
Right off the top of my head, Paul Fuji....and that's about all that he could do...and he hit harder punch for punch than Pryor for sure....add to that Carlos Hernandez.....another who hit harder than Pryor.