I worked in a car factory for 15 years, well in one of the Labs.
Almost every car coming off the final line would need some type of repair or paint correction.
These aren't Ferrari build cells, they are incredibly busy and fast factory's.
Around 40 cars an hour, off each line.
The final coat, Topcoat, is applied by robots, (because it's carcinogenic), at speed, and it's more lacquer than paint.
It's thicker, and cured at high temperature
The paint is water based, it would wash off in the rain! All repair and correction is done to the clear topcoat, not the colour.