the demographics, the club teams, the training facilities, the geography(Davis County schools are in a line up I15, Salt Lake and Utah County you'll have 5 schools within 5 miles to attend).
The part I'm not clear on is are you saying kids are moving to get playing time and that's forming super teams? If a kid were to move to get playing time that would bring more parity and break up super teams.
Also if you look at Northern Utah county, how can the open boundaries be the issue when the top teams in the state are all from the same areas? It's really the competitive culture in the area, resources for better coaches, specialized training etc.