The people that are couple of sigmas more talented than the average are unique enough. They are category of their own. So using them as pro-diversity argument is just not working. Because any person with the Turing's level of talent is already employed, no matter what other identities may posses. Brilliance overrides everything else.

The problem is that outside the likes of Srinivasa Ramanujan people need a hell lot of education to become the best. And unlike innate talent education is not equally distributed in society.

So the pool is very skewed.