Looks at EVERY football coach to get into hot water in the last 10 years: Briles, Petrino, Freeze, Chip Kelly, Mike Leach, etc. Every one of them returned to the sport or they're still coaching after being part of major scandals. The only one that didn't return to coaching was Joe Paterno because he died. Given the fact Penn State has walked back just about every penalty they incurred as a result of the Sandusky scandal, I wouldn't be surprised if Paterno, if he were alive today, would have returned to Penn State eventually (Even in a non-coaching capacity).
Winning cures everything in sports, even bad pasts. Teams are willing to overlook shady actions if they think you can bring them wins. I seriously hope USC doesn't look Urban's way, but I wouldn't be surprised if they roll the dice looking for a savior. I wouldn't put it past USC to try, but on the flip side I think Urban really is done coaching this time.