that's easy to answer, great opposition that WEREN'T past their prime, the fact that his 4 losses only come to two Hall of Famers says it all, the best win on his resume is against an undefeated loud mouthed GOAT, who went on to shock the world time and time again, while Marciano's greatest win is against an ancient broken down version of the only man who can really compete with Ali for GOAT status, apples and oranges really