While there are certainly plenty of cases where a scholarship will draw a player to a school that might not been one of their primary targets, for many of them, that's pretty much the goal - get softball to pay for college. There are also plenty cases where kids pick out-of-state schools because of a specific academic program...and they also play softball for that school.
As for North Dakota...My friend's DD at ND isn't a college athlete. She chose ND for reasons unrelated to being offered a spot on a team or an athletic scholarship. Only 1 of her 2 sisters stayed in So Cal for college, as well.
Sure IF all the So Cal girls stayed local, they would have top-level teams very year. However, life doesn't work that way. The reality you seem unable to accept is that some people - quite a lot, actually - have a preference to go to college besides where they grew up. It's a fact. Deal with it. Besides, there aren't enough roster spots available in So Cal for all the talented players in the area.
I agree with Eric F. In fact, the entire line of logic seems faulty to me. As people mature, they develop different interests and reasons for doing things. My nephew decided that he wanted to go to college in Pa (He attended Penn State, which is my alma mater, so I was pretty happy with his choice ). But before he graduated he knew that he wanted to move out of state for his professional career. He now lives in North Carolina and is doing very well for himself. My daughter is attending a college in PA (private school), but also intends to move out of state after graduation. Personally, I have family members scattered all over the country. If the "staying local" premise was true, it should work that way even beyond college, but it clearly doesn't.