You couldn't look more desperate and confused right now. My "incorrect idea" is not that January 20 is a good date for the US race, it's that early December is a good date. The US event should be the week after the high school championships (and there should be one of those, not three). That would usually be two or three weeks after NCAA Nationals.
So obviously we can't look at how many college runners ran today in January, and say that would be the exact same showing had the race been in early December.