What do driver's licenses add to safety? The only people they prevent from driving are someone who is crazy enough to drive a car without knowing how, but draws the line at driving without government approval.
If you had to do continuing education to renew your license every X years then it may add to safety. But as it exists today it seems to be more of a form of ID than anything to do with a vehicle. When someone gets hired at a new job (USA) a drivers license can be used as a part to show citizenship, which has nothing to do with driving.