>>... a roundabout system ...gave cars the right of way already in the roundabout. The system failed. Meanwhile, roundabouts in Great Britain used the reverse approach: Cars in the roundabout had the right of way. Cars entering had to yield.

I'd guess from your use of "reverse approach" that the original US system was that cars entering had right of way. Not exactly how you've written this. I'm aware of the issue as my state (MA) was the very last to switch which vehicle in a rotary had RoW.

I haven't spent time in Scotland, but New Scotland is one of my favorite places on the planet.