@firmament2x I can’t think of someone more qualified to comment than a professor who has taught at Oxford, Cambridge, Harvard and now Stanford.
Asking “how can athletic admissions be important, with no scholarships” is very strange. Go look at the lawsuit analyses which show how much of a boost this gives to the chance of getting in, compared to other factors. You don’t have to be both a 4.0/1600 student and an athlete to get in, just the latter, even if some people are both. And if you just want to list well known individuals, I have my doubts that David Hogg would impress Prof Ferguson with his analytical essay writing skills, after all that’s not why he’s there.
As to legacy, sure smart people beget smart people, but it’s obvious that if you pick the smartest from the pool of legacies (though in fact they tend to pick the richest, not the smartest) rather than the pool of all possible candidates, your average intelligence won’t be as high. Same applies to affirmative action.
The simple point is that Harvard aren’t aiming to select the most “naturally intelligent students in the world” as you originally alleged. If you want that go to Oxbridge (or perhaps Caltech).