It doesn't "do" anything right. It just happens to
    be the oldest university in the US therefore very
    prestigious

That can't be all of it, because other similarly old ones are nowhere near as prestigious. For example the College of William and Mary is 1693 and St. John’s College is 1696, which puts them older than Yale or Princeton, but far fewer people have heard of them.

    In general, it is futile asking what extremely successful
    outliers "do" right ... it would not be replicable.

Hanson isn't trying to replicate their success (found a top-tier university), he's trying to understand it.