Great guy, really cares about his athletes.
He is a very good coach. Maybe he isn't one of the best coaches when compared to elite or D1 coaches, or maybe he is, it would be hard to say without more evidence.
As others have mentioned, his massive roster probably makes him much more successful in the context of team scoring than he would be otherwise.
The combination of a nice (if remote) California area, party reputation, huge team comraderie, and extremely low entry standards means he can recruit better and more talent than all but one or two d2 schools. This huge team size also allows him to take runners that other coaches might cut and try to develop them long term. Occasionally one of those athletes makes big improvements.
IMO, he is the perfect coach for chico. If I were an athlete with poor grades, moderate talent, and from California, and didn't want to do a JC for two years to get to a better school, I would absolutely go to Chico.
If I had massive talent but poor grades, other doors would open and I wouldn't go to chico, but it wouldn't be to avoid running for Gary, it would be to get the benefits of D1 programs' money.