Grains aren't very good food until bread is invented (probably from sprouted grains, originally). Seeds are designed to keep their goodness inside, and are very good at that containment. Bread in turn requires cooking. (I wonder now if there was a brief period of surviving on raw sprouted grains... which are far inferior because they mold so quickly.)

Wisdom teeth are far more valuable to a precooking human, who has to chew constantly to break down plant cells. The extra chewing causes stress that induces the jaw to grow longers, allowing space for the wisdome teeth.

We're basically at the "awkward teenage" part of evolving past raw-food diets.