His age is fine given what he has already accomplished. He is just turning 35. We have seen other great, undefeated fighters like Calzaghe and Mayweather go to 38 or better. If he stops at 38, he will have four years...thats 8 to 10 more fights. Ask yourself how much you think he needs. For me, should he beat Fury, and I think he will, not much else for him to do. Throw in Parker (WBO mandatory), Helenius (WBA mandadory), and where does he even go from there?
The only boxer who comes close is Lomachenko. Forget the zeroes, he was beating Salido who came in overweight intentionally and he was clearly injured against Teofimo, whose lack of interest in a rematch is evident. Loma is beating up much bigger guys, something only Usyk is coming close to achieving. But I agree, Usyk has achieved greatness already.