Yes thanks Allia, that did become apparent after we'd researched that.
From what I understand, even in the US, if for example a foreign national were to have say a serious road accident or be caught up in some sort of terrorist explosion, they would be hospitalised and treated for their injuries. Emergencies would be covered, but I believe there are categories of hospitals in the US and some British people I know who did have such a road accident (minor) and were transported to hospital at which time ,they being conscious they were asked for details of their insurance policy to determine the level of hospital care they went on to receive.
So we get threads condemning foolish Brits who travel to places without insurance in place and then set up Go Fund Me or whatever to aid their hospital fees and return home. Most countries do not want to treat foreign nationals to their health care free of charge. Personally, if I couldn't afford the insurance, and it can be costly, I wouldn't go. Of course I think any foreign national caught up in an accident or for a dire emergency should receive medical care though, treatment for on going conditions are another matter.