Surely, the fact that one of these men was far easier to hit cleanly than the other has to be a major factor, right?
Frazier got mowed down twice by a defenseless guy who did nothing but wing uppercuts and push. Peak Tyson had better defense.
Tyson was superior in this area, yes Joe used some good head movement but mostly up and down Tyson was side to side etc, prime Tyson had one of the best defenses in heavyweight history.