Probably more a function of the lousy climate that half the country has during the NCAA season. I can count on about half my hand how many good meets normally occur in the north during the NCAA season. You have usually about 3 or 4 that are nice weather (if you’re lucky enough to make it into May) and half of those will have a headwind. It’s a lot easier to sprint when you’re in Jamaica vs Oregon.
That answers the “Nathan” comment above too.