The only thing that is particularly unusual about the US is that private insurance companies are probably not very efficient (admin costs are multiples of similar mixed healthcare systems).
But if you look at healthcare spending as a % of GDP: the US has the largest public healthcare system in the world, and it has a private healthcare system that invests very heavily in people's health (I think people get confused about this because US life expectancy isn't much higher but that is largely a function of things like obesity that, ultimately, aren't solvable without people eating less...the US does very well with quality of life and difficult to treat stuff like cancer, I am in the UK and a lot of cancers are treated properly, there is just no money to do so).
So, imo, the US is more expensive than similar systems like Germany. But incomes in the US are much higher, people are willing to spend more (particularly on quality of life stuff like joint replacements), and a lot of the additional cost is not in treatment but admin. Maybe moving to a public insurance system would help but look at France: public healthcare system, and doesn't spend that much less than the US (and in the US, public healthcare prices are cheaper than private but private does subsidise the public...and the gap isn't huge)...doctors don't work for free, medicine isn't free, nurses aren't free, you just pay the same but in taxes (btw, I think a public healthcare system would reduce costs by removing admin...would they like it when they couldn't get a knee replacement? No. Would they like it when a parent got cancer or their kid has a rare type of epilepsy and they can't get medicine? No...there are trade-offs, fully public healthcare systems generally do not perform as well as mixed systems like Germany or Netherlands...making insurers non-profit might be a good first step).