I think that their main contribution, was to help him to break into the American market in the first place. Once he is an established contender, he has a fair chance at winning the title, depending upon who he draws for the title fight.
Someone made a video of Briggs looking very good, even very quick for a man that size. You stated these 50 boxers were bums. I made a point Carneras opposition was on the same (or even more) bum level, even mob controlled, three weightclasses under Carnera. With one drastic difference, and thats my point: Briggs looking incredible on tape, while Carnera looked like a big oaf every time you watch him. There is just NO contrast for Carnera to make!