They were world class for their time, perhaps. But that's like saying Chris Byrd is world class. He isn't, but he was still one of the best in our era. Tyson's prime coincided with a similarly weak etra. I've already said I think he was one of the best ever in his prime, he just never had the calibre of opponent to prove it. But I won't let my favourtism of Tyson bline me to his resume, which isn't that strong. He got beaten by the best he faced.
There is no: "perhaps" They were genuine, world class fighters. They were better than the majority of today's top 20 guys. Yes, Byrd was a world class HW. What are you talking about? What is world class to you? What's your criteria? Byrd fought at the highest level. If he was active today, he would be universally recognised as a top 10 HW.
But 'the highest level' is only within the context of their era. Where would Byrd have featured in the 70's? He would be fringe world class at best.
Again: What's your criteria/definition? To me: A world class fighter is a guy who's in the mix with 10-20 other guys in his class, who's capable of fighting for titles etc. They don't have to be elite like Floyd Mayweather. Elite fighters are a notch above world class fighters. Chris Byrd would still have a been a world class HW in the 70's. As in: He'd have been in the top 10-20 fighters of the decade. We must have different definitions. Because guys like: Tucker, Spinks and Holmes, would have been top 10-20 HW's in any era. Considering that today we have the likes of Wilder and Parker considered as 2 of the best, a guy like Tucker would easily be a top 5 guy of today.
I think bums like Holmes Spinks Tucker Ruddock Berbick Golota will give current top 10 a really hard fight.