I think his point is that Harvard grads are successful more because of the abilities they had to show in order TO GET IN, rather than due to what they learned while they were there.
Bill Gates is a successful guy who went to Harvard -- but he never got past his sophomore year, correctly judging that taking advantage of business opportunities in the computer area was a better idea than going to class.
Which is why they are a benchmark.
Author of this piece went to liberal arts school Rhodes College. Notice her handle "sarahcuda"