I have no wish to get involved in this debate, but in the 90s one of my relatives went to Germany from England for a needed heart operation that he couldn't get at home. If he hadn't done that, the other options were France and the US. Their perception is that the UK has created a two-tiered system, where people who could afford better treatment or insurance (or spend their life savings for it) can get it privately, and the masses get ok but universal insurance they have to wait in line for.
The benefits of the UK system, which my relatives understandably don't really see, is that there are *much* lower costs per capita, and universal coverage, which theoretically provides for better average outcomes. The thing with US healthcare is the costs. No matter what side of the debate you're on, we pay by *far* the most on healthcare in the world, without appreciably better outcomes.
More food for thought is healthcare research. Private companies fund a lot of research in the US. If they weren't making money on it, they'd cut back and that would take a lot to replace (the US alone historically performs about half of all healthcare research in the world). Our government is already heavily subsidizing research as well so it won't be a matter of just shifting the funding to the public sector. Europe and some Asian countries are increasing their output, but still aren't remotely close. If American research declines, either other countries will have to subsidize a lot more than they've historically been used to, or it won't happen at all.