rumor has it Ghengis Khan introduced folkstyle wrestling to that region and they've been doing it ever since. That's how Ghengis Khan kept his warriors physically fit he had them wrestle each other all the time. Also that region has seen a lot of warfare with invasions from Arabs, Turks, Persians, Huns,Mongols,Russians so whoever came out alive retreated to the highlands up to the highest peaks to have a tactical advantage over their enemies. Which through centuries kept them physically fit with the high altitude air and constant work of herding sheep and farming. It's the same with America the best wrestlers are from farm boy states where they have good day to day physical work ethic.
It's all adaptation and survival