This man has accepted his fate. All the drugs, the drinking, the battles of his trade, they all have taken their toll. We can see it in his face as well as the scars that mark his body.
What allows The Wrestler to leave such a lasting impact is that we can all recognize the face Randy wears at the end of the film. Acceptance. He does not care if he dies in the ring because the ring is the only place that really allows him to exist. Life has chewed him up and spat him out but here, among the cheers of his legion, he is King.