Perhaps the rich

I don't know if that's serious or snark, but I don't think it's necessarily the rich. For instance, the management class could absorb the positive externalities of their more intelligent and less socially adept subordinates while only being marginally richer. So, as a whole if you could say the management class produces no to few benefits themselves, and yet takes a huge chunk of economic wealth roughly the size of what you'd expect from the positive externalities from intelligence, then you could potentially make some interesting conclusions.

ETA: I'm using this as an example of the kind of thing I'm talking about, and I'm not supporting it as a conclusion or even a hypothesis.