It's funny, the Ivies are actually quite up front that they're goal is to pick "future leaders" of the country, not the most academically gifted students (though this is an important sub-group). The fact that there's a quota of students who are chosen for purely academic talents is particularly telling.

If you have enough drive to get good grades and your parents are worth many millions of dollars you have an excellent chance of being one of society's future leaders, you're they're perfect candidate.