The answer is that our healthcare system is currently undergoing the greatest structural market reform in the history of its existence, and it’s happening along American healthcare lines.
There’s nothing American at all about how the NHS is being reorganised.
True, ACOs exist in the US. But they’re an attempt to move the US health care system in a more European – continental Europe, not the NHS – direction.
Quite apart from anything else they’re found in Medicare – government paid for medical services.