Well I'll try to give it a shot and hope others will chime in.
Hatch Green chilies are like many grapes, grains or hops in the sense that they come from a special geographical growing area which, in this case is Hatch, New Mexico.
Like most agricultural products that have gained a following it is the climate, soil conditions etc. that make that pepper, grape, grain or hop so prized.
You can get the seeds of these plants and grow them elsewhere but they just won't quite be the same.
So when a particular crop gains this kind of popularity supply and demand economics kicks in so that all the farmers want to grow that crop for higher profits than something else, like cotton.
What makes that important is that like Oregon State University and it's state backed (funding) hop research program New Mexico State does the same with the chilies.
They start looking into disease and pest resistance, cross cultivation, crop yield etc and developing improved varieties for economic benefit to the farmers of that region.
That was the long version, the short version is that New Mexico's Hatch kick the crap out of California's Anaheim.
