When you consider the complexity of the act of driving I'd say a majority of people driving are pretty good drivers, the alternative would be a significant accident rate resulting in impassable roads.
To me this is really a point about just how good the interface of wheel/pedals is, that any moron off the street can be taught to drive in a matter of hours.
Yes, any moron can learn the basics of driving in a couple of hours but they’re far from average or good drivers, it takes a bit more than that to become an average driver and there are still some factors at play which might influence that: spatial ability, reflexes, attention span, how one handles stressful situations. But a moron can be a good driver without being smart about other things or having a good education