Why did Frazier fight Foreman twice?

I wonder how the hell Ali was able to fire right handed lightning bolts with that kind of speed and push Foreman off the way he did while his back was braced against those loose ropes. Using tight ropes as a slingshot, he'd have been ricocheting those right hands even faster, and had his back more securely braced for shoving George away from the ropes.

Foreman II might have been as bad an anticlimactic mismatch as Frazier-JQ and Ali-JQ II were for Jerry. George did not fight as stupidly as commonly derided for in Kinshasa. He teed off repeatedly with right hand bombs to the body on the older man, and they just had no effect. Foreman had put opponents down for the count with single body shots like that. He did not have Ali's reach, speed or straightness of punching. He was not capable of knocking Ali out. Kinshasa went the way he wanted. He cut the ring off, got his man on the ropes for the opportunity to bang away, and it backfired.

George has admitted countless times that the right hand he unloaded which caused Ali to taunt, "Is that the best you've got?" was the hardest punch he ever attempted in his career. He's conceded that's when he knew he couldn't knock Ali out, and this is somebody who has asserted numerous times that, unlike Shavers, he never went into a match looking for a decision win, only a knockout. (Earnie came into Henry Clark I with a bad right hand in Paris, and showed he could stick and move with his long jab for the win by keeping matters in center ring. His high school background as a gridiron lineman gave him a measure of lateral mobility one might not have expected of him. This was the television broadcast commentary debut of an extremely bewildered Larry Merchant, who found himself trying to assess a bout which turned out the complete opposite of what everybody expected going in. For the rematch, the Shavers right was fully healed, and it showed.)

Put Ali and Foreman in MSG for a rematch. Air conditioning, a ring acceptable to both, and so forth. We know George is still going to have to go for a knockout. At close range, he gets smothered with his neck yanked on (not that it would matter, after Padilla prevented that tactic in Manila to no avail for Frazier). If flat footed in mid ring at long range, Ali's speed and straight punching allows him to hit w/out being hit. Foreman will be invited by Ali to go after him against the ropes. Do you think there's any way George would accept that offer after Kinshasa?

Earnie Shavers had underrated hand speed, underrated skills and boxing smarts as he showed in Paris with that bad right hand for Clark I, and the late round power to put three different opponents down and out in the tenth and final round, and put Tillis flat on his face in round nine. Foreman produced no career knockdowns later than the fifth round against Lyle and Frazier until his second career. No question who had superior late round punching power. Shavers didn't usually pace himself well, and didn't have the physical template for good stamina with his club like arms, but he was the best conditioned heavyweight in the world, and a far better candidate to compete with Ali over 15 rounds than George ever could have been.