The countries, that are not US get better bang for buck, because the US overspends on healthcare. 99% of the new drugs and medical devices are brought to market first in US. After the US pays most of the R&D expenses the rest of the world gets stuff on the cheap.
There are limited resources, somebody has to make hard decisions - e.g. if a given patient must live or die. Is a privately owned insurance company a better choice maker, than the government in this case?
Is it a bad thing to have millionaire doctors, specialists or dentists?
Should ideally everybody be poor?
Or is wealth reserved for celebrities and members of a few special families?
Healthcare is important and it's OK to spend a ton of money on it. Decreasing the US expenses on healthcare will have a global negative impact on life expectancy, quality of life and medical research, as the US is
effectively subsidizing healthcare in all other countries. That's perfectly fine as the rest of the world uses the dollar to trade and as reserve currency, subsidizing the US government and economy.