Why can't the opposite be true; those without an overbite are able to survive/mate better in the absence of utensils? Then the modern presence of overbite is e

Why can't the opposite be true; those without an overbite are able to survive/mate better in the absence of utensils? Then the modern presence of overbite is easily explained as genetic drift. I would guess that many modern mutations could be explained this way -- human invention alleviates evolutionary pressure keeping historically negative traits from flourishing.