> What happens when it's illegal to buy the only cars that are available for sale?

Wyoming will start to look like Cuba: people will drive antiques, and local machinists will crop up to reproduce out-of-stock parts. They've got oil, so presumably they could even maintain their own gasoline supply through corporate welfare. As the second least-populous (people per square mile) state in the union, I think they could even pull it off.

Richer Wyomingians will be able to buy electric cars out of state, but if it gets that far, I suspect such a choice would bear substantial physical risk even driving around in one (which is already a nuisance in some places).