Won a world title in his 10th pro fight Is one of only a handful of fighters to hold all 4 belts, and did it in just his 15th fight Is one of only 3 fighters to win a world title at Cruiserweight and Heavyweight, and one of only 7 to win a title in a lower weight class and Heavyweight (Fitzsimmons, Spinks, Holyfield, Moorer, Jones, Haye, and Usyk) Having accomplished all of this, is Usyk an ATG?
On his way, post-fight hype of Usyk is sweeping this forum, give it a week and the logical opinions will come. Right now, after defeating the forums enemy, AJ, of course that will make the forum put him in top 20 of all time.
On face value of what he has accomplished Yes. However there are several trains of thought on the matter. If you subscribe to the theory that Athletes have become bigger stronger faster, and have taken better care of themselves. (better diets, nutrition, less alcohol, no smoking) then Yes If you also subscribe to belief that Boxing has become more global and therefore has a deeper overall talent pool than the American centric version that dominated the last 100 years than also yes. If you subscribe to the belief that boxing as a barbaric way to make money has led to the best athletes, with many more avenues in the modern world in sports to make money has depleted the talent pool then No. I lean Yes
Do you need to ask? Wins over six champs in two divisions, some of them vary good, in 19 fights. If not Usyk, then who?
Obviously, he's an ATG cruiser and a first ballot HOF'er. I would, however, like to see see how the remainder of his career plays out before I christen him an ATG in general.