You can get away with forgetting a lot of things you learned in high school, but how to drive definitely isn't one of them. The info you crammed while in line at the DMV likely didn't stick two, three ...
Overall, it would be better for the general public if every driver were better trained before getting a license.
For many people, taking a driver education class is a teenage rite of passage. They learn the rules of the road in the classroom and try to avoid flattening too many orange cones in the school parking ...