If the "objective metrics" are useless discriminators, then the only effect of using them is to make us feel as though we have control over a situation that we don't understand. In that scenario, it makes far more sense to restructure the game to allow more initial participants, and to cull the best players.

You seem to be arguing that we must have "objective" filtering mechanisms, even if they're random. Gladwell is saying that the whole paradigm is wrong.