I'm not sure what the "broad sociological foundations" might be, but there are certainly a lot of areas up North and in the Midwest, Great Plains and all the way out to California that don't have the Scots Irish influence.
But there is one common factor that always seems to be at the heart of an area getting started and then staying tough - that's the development of a great (not good, but Great) feeder program that gets a school or two up and going, then helps them stay up for a while and then just keeps on pouring in new experienced freshman kids each year. As the success builds, then the younger kids look up at the high school success and want to be a part of that.
Somebody needs to ask Alan Morris what it was that got him to keep going with the feeder program he ran in Cleveland for 18 years. He certainly pumped a lot of future state champs into the Bradley program.
I remember taking a USA Wrestling coaching certification class from Al Miller at Cleveland about 8 years ago. The first question he asked was "What's the most important factor that contributes to a successful high school wrestling program?"
The answer was "A successful youth wrestling feeder program".
So, if anyone wants to know how to build an area, it's simple - just go out and recruit several former wrestlers who are willing to put in years to build the feeder program, give those kids to a qualified, passionate high school coach and see what happens.