Speaking as a quality control chemist for a paint manufacturer, believe me, it's not less expensive having to reformulate existing products to meet shifting environmental standards. Most of the trouble is that not only is there a national standard for maximum VOC limits, but many states also have their own limits and in some cases theirs are lower than the national standard; think of California and their CARB B.S. for vehicles.
It can also be pretty tricky getting the new formulation to at least act similarly to what customers are used to seeing.