First, I don't think this conversation is about CESA anymore. CESA simply announced it was going to offer training in the Rock Hill area...no doubt due to demand from parents and players. CESA has offered Columbia training for years (GFC did before CESA) without it being a big deal to anyone but the kids and coaches who participated.
Okay...moving on. York County has rougly 3X less people than the Greenville, Charleston, or Columbia metropolitan areas. Thus, as you're planning in the long term how to build state championship teams, you may want to consider either (a) having a 300% greater penetration rate of youth playing soccer in the area or (b) drawing players from Charlotte.
Does that mean it can't be done? Heck yes, of course it can be done...penetration rates vary widely in different states and great programs draw from a wide radius.
