Did Usyk end this discussion with his win over AJ? On one hand, there are people, who think that the HWs from the past would be too small to compete with the modern HWs. On the other hand, there are people, who think that the older heavyweights were smaller, but they would make it up with better skill in a H2H fight. Usyk's size in his fight with Joshua is comparable with the heavyweight's from the 70s imo, even though you could make a case for exceptions even much earlier than the 1970s (Sonny Liston, Joe Louis, Jack Johnson etc). Did Usyk's win against Joshua proof, that the skilled smaller HW's like Ali, Holmes, Liston, Louis and Frazier (?) would beat todays SHW's like Wladimir, Vitali, Lewis, Fury and Joshua?
None above its the fighter that makes the diferance. Tyson proved that in 80's Spinks also So did holyfield Byrd to lesser degree If the big guys are very good like Lewis or k bros then it gets harder or impossible. Also styles makes fights. In klitschko era only only 2 fighters had unique style Byrd and Haye.
Case by case. Eventually they’ll get too big but as of now Usyk has proved 6’3 guys still have a huge place in HW. The big thing about Klitschko is that being 6’6 was still rare (No Yoka, Joyce, Hrgovic, Dychko, Jalolov, Joshua, Fury, on and on) so he engineered his fighting style to crush smaller guys. Nowadays you can’t focus near purely on beating opponents 2-5 inches shorter than you even if you’re 6’6 or 6’7, because there’s another big fish out to get you. 6’6 guys aren’t any less human than 6’3 guys.