For example, the US is by far the world leader in medical research spending - 44% of global medical research is spent in the US. (Until recently it was even higher). [1]
On the same note, many nations regulate the price of prescription drugs - drugs where the initial R&D was done in the states. (Yes, drugs are sold at a huge markup, but that's to recoup the huge initial costs of research). In other words, Americans are taking it in the chin to invest in pharmaceutical innovations, which other countries then treat as a public good.
An additional point that's often obscured: there's no purely capitalistic healthcare system in the world. Even pre-Obamacare, the US system was about 46% funded by the government. (As with the US education system, the availability of government funds has massively pushed up prices). [2]
On a personal note - I'm a brit, but I've lived abroad, and the NHS is one of the reasons I'm considering settling abroad long-term. I simply don't trust the organisation as a whole to take care of my health. If you get assigned a good doctor for your condition, you're OK, but I have my own stories (and I've heard many others) of conditions being ignored or misdiagnosed, even after multiple visits.
In contrast, I went to a hospital in Bangkok that was of far higher quality than the average NHS hospital. (Granted, this was a private hospital, but it puts things into perspective). One Israeli friend said that walking into a UK clinic was like walking into a clinic in a third-world country. It's shabby, the wait is long, the bureaucracy is confusing, etc.
Strange as it may sound, I trust a for-profit entity more with my health, because their livelihood directly depends on taking good care of me. The common argument that healthcare can't be a market because of information asymmetry and doctors being in a position of power doesn't wash: the same holds true for other complex services, like auto repair, and the solution is simple: third party reviews. (On the moral argument, about affordability, I think with a truly private healthcare system entrepreneurs would be able to drive the costs down for people on middle-incomes, and only the bottom 15-20% would be reliant on government or charity spending).
[1] https://www.urmc.rochester.edu/news/story/4233/u.s.-slipping...
[2] https://en.wikipedia.org/wiki/List_of_countries_by_health_ex...