"Even within the US, where the regulatory environment, market size, and other confounding factors can be ruled out, they have all failed to varying degrees." I

"Even within the US, where the regulatory environment, market size, and other confounding factors can be ruled out, they have all failed to varying degrees." I don't believe that's true. Regulations in California are quite different on a number of topics to the rest of the country. Specifically the prohibition of non-competes.