Blue made a good point. Heybucket is a pastime of those trying to kill off a workday. Other than that though teams don't travel from SoCal to NorCal looking for games. The reason being is NorCal is willing to travel! There is no other reason.
It's numbers people. There are more people in Orange and LA County than from the Grapevine to Oregon. NorCal will have a national contender in every age group, but SoCal will have two. SoCal does a better job of making the establishment. I would say the Sorcerer are the only thing close in NorCal (ie coaches stay in the same age and kids are fed through). Softball has branding, too! Everybody wants to be a Firecracker for a reason, no?
I'll even go as far as to say the best athletes don't play softball. You lose too many kids to soccer.