I honestly dont think he's completely past it. He's obviously not as good as he was in his prime, but he also suffered poor form under Ange tactics. He was forced to play a winger who went wide, was supposed to beat his man, and cut it back. None of those have ever been his strength.
Ange ball also neutralized his strengths - cutting in on the low block, and countering into space.
I obviously can't be certain, and i dont fault him at all if he wishes to go, but I do still think he has one or two more seasons as one of the Prems best scoring LWs under a coach who plays a system that plays to his strength.