People from the 'top-tier' schools are shooting for a multitude of things besides entrepreneurial success. I graduated from UChicago, and it seemed as if a massive majority of my fellow students were going after law, banking, or academia. At my five-year reunion I was one of the only people I met not pursuing one of these paths. In addition, many students at these schools have some kind of anti-business ideology or another, so subtract them from the picture as well.

I agree that there are probably more great teams from the technical universities and high-end state schools than from the ivies and famous private universities.