You can find plenty of people who were at ringside who expressed their opinion that LaMotta fought badly, but honestly. Including LaMotta himself, of course. There was a rumor that Silvani and Jake's father confered with Palermo before the fight. Must have been true.
Silvani never managed anyone again? Big deal! Who else did he managed and for how long, other than LaMotta for a short time (not really being a manager per se, only called as such) and Mauriello while the latter's manager was in the army?