Yes, he combined phenomenal defence with being extremely fit, so could most often outlast other players. He won a ton of tight matches that way.
But now he is 35 with a metal hip - that route to success isn't available now, and it is too late to change other parts of his game that much. He's given his comeback a real good go, but I can't see him accepting touring at this lower level for too much longer.
I agree with you. And how to build confidence?