"You know this may be my last fight. Its getting too hard to train and keep in shape. I've been slipping and suddenly it dawned on me . I worked like a horse getting ready for the Walcott fight. I worked almost as hard for the rematch. Since then I've had 3 more defences, and I've been doing less work and training for each one. I was counting the other day and it scares me. For this match with Moore, I've boxed only half the rounds I did preparing for the first one with Walcott. You know what that means? I've lost the hunger or something. It means that someday I'll go into a fight in less than perfect condition and I'll get whipped. I think I'll quit before that happens to Rocky! I'm too proud to let Marciano lose to Rocky Marciano. Yeah, I guess sometimes you lose the hunger." -Rocky Marciano interesting stuff
Like most champions he got complacent and comfortable! He’s not alone as I’d say a majority of them very much did the same. He just got out instead of chasing the next pay day. Didn’t help he hated his manager and didn’t want to give Goldman a penny more (was signed for one more fight w Goldman so if he ever fought again he was obligated to go through him).
He loved the Italian food, and he loved the ladies, who loved him back. He denied himself both when he was in training. Hence, the short career. Only fight left on table was Nino Valdez, and even that had past its expiration date. People thinking that beating Satterfield or Baker would have proved anything are kidding themselves.
I think that Rocky Marciano did not have the hunger anymore which is a recipe for defeat, much the same way that Larry Holmes went into the 1st fight against Michael Spinks, 30 years to the date of Rocky's victory over Archie Moore. That attitude cost Holmes the ability to break Marciano's record. Charlie Goldman and Al Weill always had Rocky train hard but, his heart was not in it anymore. Imagine had he continued fighting into 1956, and a fight against a hungry young Floyd Patterson would have happened. Cus D Amato would have had Floyd in the best shape of his life, Patterson might have become the new champion. i believe that another of Al Weill's fighters fought Floyd Patterson on Aug 18 1958, Roy Cut N Shoot Harris.
Physical pain can dull with the will to compete, Rocky knew his time was nearly up. His back went out on him, and that was it. When a swarmer type loses his stamina and speed, it over.