Is it that the top funds are packed with smart people, or there are smart people at the top of a lot of funds with lots of less-intelligent junior people?
From what I've seen, the top funds (at least the smaller ones) are 75+% smart people (at partner level; I never met enough associates/principals to evaluate them); there are entire bad funds full of mainly dumb people from the top down.
This is kind of different from operating entities, where even stupid-dominated organizations often have some great people hiding out, or even entire great teams.