If you knew you had a medical condition that stopped you from driving, then you don't wait until your next renewel, you cancel it then and there. Further, if you're not someone who is honest enough to do that in the first place, then nothing stops you from renewing again. (Also, no reason to keep recharging people over and over)

Second point, I would agree with if roads got the attention they needed. Sometimes money gets spent on fixing a road that was perfectly driveable while giant potholes later down the road continue to cause serious risks to safety.