Good assessment, generally how I figured it to be as well.
Geographically, and probably politically, SDSC is frozen out of higher competition beyond DSL. The G2010 example, and many other very good teams, are a testament of the large and strong community base of young players that are forced to depart the club early on to continue developing and playing at highest levels with DA/ECNL. It's hard to achieve championship teams when they're gutted at early ages...it has become an unfortunate cycle.
There is a great pool of players in the SDSC footprint...but my family has long since had to move on from SDSC. I know many families, mine included, that much prefer staying close to home with SDSC and build national class teams...Unfortunately, Surf knows this as well.