I'm sorry but your wrong, even a totally washed up Ali was able to ggive Trevor Berbick a competitve fight at the end of his career, people are always talking about the Berbick fight like it was a huge disgrace but Berbick was actually a very good fighter and even when he had little left Ali could still compete with him... the Wepner thing is just silly, Chuck was a hardened pro by the time he fought Ali, big difference to going straight in with Ali in your first pro fight... as I said before fighting amutuer and pro is two different worlds and I doubt Stevenstop would cross it successfully in one fight against a man like Ali....
I quote Trevor Berbick on this particular fight:
'It was a great motivation to fight him. But then there was a sympathy. I'm saying, how can I really, really hurt him? How can I try to hurt him seriously? I was hoping that I'd hit him and he'd just go down and out instead of banging at him hard. I knew I had to do what I had to do. So I stayed with the body because I figured it would do less damage. And I scored alot to the body. Even when he was on me I was punching tremendously. That's what won me the fight.'
Berbick wasn't going full out on Ali, he was taking it easy on him. So I don't exactly agree with what you're saying, at least when it comes to this particular fight. Neither was Larry Holmes, he wasn't going all out on Ali either, yet Ali was getting the crap kicked out of him. Sure Ali could take punishment against the top guys---but he couldn't beat nobody with anything at all going for them.
As for Wepner, while he may have been established as a fighter, this man was still working as a liquor salesman. He wasn't training full time for fights, he was fighting club fighters for the most part. Read any interview with Wepner and he himself will say that the Ali fight was the first time where he ever trained full time for a fight in his life.