It's somewhat pointless to speculate this imo. Of course the beating Joe laid on him affected his confidence and will always give his opponents more of their own having seen how badly his flaws could be exposed. Having said that he wasn't ruined before he fought Calzaghe(not that he was after neccesarily), and yet he got as one sided a beating as a fighter can take, because he had no ability to deal with Calzaghes pedigree or athletecism, he never did. It's not as if Calzaghe was his kryptonite, he just had the perfect style and attributes to do an unruly number on Jeff. I know that seems contradictory, I just mean it's not as if Joe NEEDED to perform that well or do half of the things he did that night to hand Lacy his ass. Of course it's unlikely anyone else would have given him a beating of the same magnitude, but that's just down to styles and of course Calzaghe being far and away the best supper middle out there at the time. I doubt anyone really feels that with hindsight had he not lost to Calzaghe he would have cleaned out the division or beaten a Kessler or Hopkins, even Taylor at any point.