After all, Harvard wants 1,600 or so students to matriculate. They will accept 2,000 or so, whether 57,000 apply or 5,700 apply. Because so many apply, they can use criteria that only cover 1/100 of the population.
That makes them “extremely selective”, but does not inherently imply that the criteria which they use result in their selecting the “best” students, by any objective measure.