I don't think this statement has much substance in it because of the following reasons:
First off, as for as matching the color is concerned, it's been made easy by predefined computer coded colors used by all major dealerships. Now they don't need to take off the fuel tank lid to mix n' match the color. So, color matching is no more an issue for new model cars at least.
Secondly, dealerships have been in business for years, they are not too dumb to overlook the sun factor before investing millions in Paint booths.
In my opinion a bad paint job is directly related to the painter's skills, spraying gun used (as mostly they use single spraying gun for different colors) and no. of coats applied.
If they replace human painter with a robot (which requires electricity to operate and very scarce in our country :), I am positive that there will be less inconsistencies in paint jobs.