I'm not saying it would have to be a product of enforcement. Although unlikely, it could be one of education. Enforcement depends on the country and it's governance. For example, you would need a constitutional amendment in the US to impose those sorts of restrictions. It would require the representation and buy-in of the people (so education is an important part either way). Then you also have game theory with how to compete on a variety of issues internationally depending on population dynamics.

That's also only half the issue. The other half is the consumption. This would likely be more achievable through taxes, zoning, and the court's (potentially flawed) interpretation of interstate commerce laws.