Not sure where Neil got his information but there are roughly 20,500 high schools in the USA.
the Harvard freshman class is about 2,000 students a year. So do the math, most high school valedictorians will be rejected, if they even apply to Harvard.
Perhaps a side issue, but does every one of the 20,000 plus valedictorians even apply to Ivy League schools?
It was on my feeble memory, not Neil. I couldn’t find his quote so put it out how I recollected.