How do you define "work" in this context?
Good question.
In the UK we have slightly better health outcomes than people who get US healthcare. The NHS covers the entire population and health care is free at the point of delivery. It costs about half what the US system does.
I guess that is what I mean by a single payer system "works."
Of course not. Google it - the health care industry are very well researched. And the US one is unique in that it gives huge IP protection and tariff walls to vendors and then calls itself a "market."
That just means that care costs more for Americans, on average. Of course it does. That doesn't equate to UK residents having better healthcare, better access or better outcomes. The reverse is generally true.