Yes, although he made a comeback and get his fans excited, I doubt think that he can bring back the clock. He might be satisfied on entering tournament and see how far he can go or even winning (and losing) against young guys.
I guess though the competitive spirit is still inside of him. Nevertheless, might be in a couple of years he might go and retire.
I think he also enjoys it just too much. Otherwise, why would you keep competing if you know that you can't win anymore against players that you defeated easy on years ago.
He can indeed win the first couple of rounds, even against keep players, but that's about it.
Maybe, he is still enjoying playing against this young players and he wanted to proved that he still has it. However, it's two different things, maybe your mind is telling you to go and play, but if your body is not cooperating because of injuries and you are already way past your prime. Then sooner or later you will have to make that difficult decision just like any other athletes, it's just to retire and no need to push yourself anymore and let this young blood be the next of the generation.