It's going to take more than a new HC to change the direction of that franchise.  When ownership ditched San Diego, they alienated a significant portion of their loyal fanbase in a notoriously fickle market for football at all levels.  San Diegans are not road tripping to LA for games.  LA pro football fans are split between so many teams there is not a clear hometown favorite (Chargers, Rams, Raiders are the top three in that market).  I attended a Charger game there last year as a fan of the opposition and the opposition fans were more numerous and louder than the home crowd.  SoFi is a palace dropped in the middle of an extremely depressed locale and it appears the shine stops at the edge of the parking lots.  

I can go on and bitch more, but I think you get the point:  LA sucks for football.

While it would be nice for Herbert to "succeed" Fouts as a Charger legend, I don't think anyone in that area cares.  Hopefully JH is traded or hits the FA market and lands with a team and fanbase that actually cares.