You're missing the point. Agassi has always been about no regrets. He couldn't live with himself if he retired knowing that he could have kept going. Last year's US Open was one of the highest points of his career, he was seeing and hitting the ball like no one else. No way he'd retire after that. If he hadn't turned his ankle, things could have been different. Who knows, maybe one day he'll wake up and his back and legs will feel great and he'll pull a Rocky Balboa and play in another tournament.