Us does spend the money on healthcare, it is just very inefficient. US government spends much more per capita than any other country. 50% than the #2 country, Germany.
I don't know where you're getting your numbers but according to OECD, the per capita spending in the US is 13k. That's public and private spending. I don't think your 12k per capita number is just public spending.
https://www.statista.com/statistics/283221/per-capita-health...