I agree that lines should be fixed, however humans rely on things other than lane lines, and autopilots should too. When you can't see you get cues from other cars, estimated distance from both sides of the road, sign placement above your head or on the side of the road, etc...

If we need to repaint all roads to make them work for auto-driving cars, we might as well just move to one of those simple systems like where a robot follows a pre-drawn line on a piece of paper. Maybe throw some bar codes in there so the car knows where it is.

If the cars can't deal with environments that even humans can, I'm not sure what the point is anymore. I expect a self-driving car can see through things like fog and darkness better than a human.