they were all old. Also Usyk may only have four but that leaves out Chisora and Dubois. Usyk has better prime wins than Marciano
Moore had like a 67-4 overall record at Heavyweight and had beaten all the top Heavyweight contenders who would be considered big for that era like Valdes, Baker, prior to facing Marciano. Charles, Walcott, were past it yes but were still coming off good performances prior to facing Marciano. Even Louis had some decent wins like beating Bivins. Fury is past it aswell although Usyk is also past it so it evens itself out. But still Marciano has beaten more ranked fighters, beaten fighters who are considered great unlike Usyk, and has more world title wins.
Nice, there is a lot to watch back. Most of all Holmes. I think I only saw one of his prime fights once and the Tyson fight late in his career. To me he always fell into the nowhere land between Ali and Tyson, but since so many have him so high, I will try to watch more. Also have to watch more Louis and Marciano fights. From Louis I saw mostly Schmeling and Highlights and and I didn't see more than two Marciano fights. Also I got interested in Gene Tunney Which fights of those fighters would you recommend?