You admit the "skull and bones" kid because he will bring money and influence to the school...money that can then be spent on kids with more "g," as you put it.
The skull and bones kid is probably going to do alright in the world, even if he is a jerk (I'm playing along with your sterotypes here). The kids with high "g" are, like startups, a bit of a crapshoot. You might get David Foster Wallace, but probably not. Either way, the "g" kids aren't going to bring home the bacon.