I agree with you. It's over for Peter. He has "learned" how to lose. Many boxers never recover from a loss where they were totally dominated, Peter fits into that category.
Peter's chin was always decent but it's certainly not granite, he WAS undoubtly going to get stopped by Vitali had he stayed in the fight. After eight rounds of one-sided beatdown he was ready to go and Vitali would have gone for the kill in the next few rounds.
Peter was staggared in the 8th, was exhausted, getting the hell beaten out of him, and was on his way to being KOed, and he knew it. Had he not given up, I think he'd have been taken out in the ninth; tenth at the latest. The two losses certainly took him down a notch or two, but he will almost certainly work his way back to yet another title shot. He is a big puncher (although overrated power), and has only suffered two losses to the two best in the game. Nothing to end a career over.
I agree. Had my doubts after the McCline fight. But now I think his chin will exhaust Haye and then knock him out.