The private insurance expenditure is part of that per capita number. US healthcare isn't "A system", its a number of interrelated systems that have lots of expensive hand-offs. We also spend a ton on lifestyles diseases because no one walks and culturally we eat like shit on average.
The graph shows both public and private expenditure. If you only consider the public per-capita expenditure it's more than every other nation on the graphs public + private per-capita spending.
> We also spend a ton on lifestyles diseases because no one walks and culturally we eat like shit on average.
And there's a pretty straight line between that and government subsidies for sugar and processed foods in general, not to mention car-based infrastructure, although the latter doesn't stop other countries from not having crippling obesity rates.