How does a Californian company compete with a company in Missouri that has lower labor costs and less overhead/ regulation?
They seem to manage this just fine, but it's a pretty similar scenario. You could also push for standardized business costs and regulations eu wide ofc to help.
The Californian company probably opens their new plant in Missouri, so now it's not exactly a Californian company.
Standardized costs would just hurt the poorer members more. You’re underestimating the economical difference between EU member states. It’s more like if Californian businesses had to compete with Mexican in a single market, and Mexicans would be paying Californian prices with Mexican wages in the end.