How about voltage / current / communication? Seems quite a complicated problem, it's not just a case of different USB plug styles..

Actually USB is a great example.

USB C can charge at 5v, 10v, 20v, etc. When you plug in a device to the charger a hand shake happens between the charger and device and they choose the voltage and amperage that makes sense. A macbook pro can take 100W over USBC but obviously your headphones or phone aren't going to.

It actually is very similar to USB plug styles. NACS communicates the same way that CCS does. Converting between NACS and CCS1 or CCS2 connectors should be easy.

The biggest issue is the amount of current involved.

The voltage and current are determined by negotiation between the car and charger. There were plenty of US Teslas imported into Norway in the early days. They have no trouble charging here. If necessary a simple conversion can be done.

Making my 2015 S70D that had a Type 2 connector work with CCS2 was a 300 USD conversion. I can't see any reason why converting from NACS to CCS2 would be any more difficult or expensive.

Tesla is using the same communication standard, they just combine AC and DC on the same pins which means an adapter can be pretty cheap.

Remember teslas come with a CCS adapter that can go the other way.