That's exactly the point. Top schools are looking for outlier intellectual talent, but the egalitarian approach (high school grade inflation plus weakening of standardized testing) smooths the differences and makes it harder for them to admit the right people.

The visible result has been the weakening of these institutions. Do also observe that this is recursive — as these institutions have lowered their standards over decades, the people who go through them and end up leading them are weaker, too.