Can you name a single school whose runners have done more after HS than Great Oaks, FM, and so on? The kids at those schools aren't more talented than other schools. They just get more out of what they have. It isn't like there is any high school (well outside of St Patricks) that has a graduated dozen of guys who later ran 3:55 guys. There is basically no evidence that the sub 4:00 guys are burning out because of their training. They improve or don't improve just like guys who run 4:05-4:20.