Usyk was slow and weighed in at his heaviest weight ever. He clearly didn't train hard for this fight. He took it too lightly. That doesn't erase the fact that he's already Fury, Dubios, and AJ.
Usyk is 39yrs old. Eventually there'll be a new generation of opponents People will demand that he face. If he keeps Fighting and tries to beat everyone eventually he'll lose. Father time is undefeated.