True the laws were started in Cali but do you see any manufacturer having two paint lines? The reason car makers are working towards even more stringent MPG standards for 2025 is because Cali wanted a tougher law then the 2016 one and car manufacturers didn't want to have multiple setups for emissions and MPG. So they are advancing it themselves. It's cheaper in the long run to just do it one way that encompasses everywhere. So all manufacturers switched as time went on. Perhaps the solution is more paint/thicker coat.
