I'm speaking very broadly, about tens of thousands of years of human history across multiple continents and contexts. And where you find the fine careful paintings of wildlife you DO NOT find human faces.
I think it says that people must not have felt motivated to make such drawings of the face, that they didn't like it or see it as useful.
They also didn't do drawings of IDK, insects very often. Insects were not as important as the large animals they hunted and that hunted them.
3/