"(fact) America is a single market with a single language with basically a single set of regulations."
I'm probably being pedantic, but: the "single set of regulations" really is an oversimplification. Each state has it's own rules in addition to Federal regulations (trying selling cars in California that meet Federal emissions standards, but not California's). Plus, there are state taxes to consider.
Compared to the difference in regulations between France and Germany, _let alone_ the difference between France and Nigeria, US states have very little to differentiate them.
I'm probably being pedantic, but: the "single set of regulations" really is an oversimplification. Each state has it's own rules in addition to Federal regulations (trying selling cars in California that meet Federal emissions standards, but not California's). Plus, there are state taxes to consider.