The best measuring stick for a fighter is another fighter. And you can only be measured by someone who's available at the time to fight you. Thus the question of this thread: Imagine for a moment that Dempsey and his best HOF contemporaries (Tunney, Wills, Sharkey) were only as good as somebody like Brian London. For purposes of this thread, assume that they would probably split series with London if they were time machined to the 60s/70s, and would amass about the same record as London did. If that was true, and they were only as good as Brian London, could we even tell? If so, how?
I don’t think their techniques would be as revered by historians and trainers as much. But they’d still be entitled to whatever legacies they established
For me it wouldn't mean that much. I think the greatness of a fighter should be judged on his time and circumstances. Another important aspect is the quality and quantity of the respective competitors. For instance, there is a difference if somebody is the best out of 10 or out of 1000. That's why it's not possible without comparisons between different eras and it's of course subjective to a certain degree. Everything else (H2H) is just speculation, can't be proven, depends on different styles and might be even unfair due to various respective time conditions (ruleset, technical and medical evolvement, historical circumstances, nutrition and other stuff...). It should only play a minor role, if at all.