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.
This can be a problem, especially for the elderly. In France the retired (pensions are publicly funded) save 25% of their income on average, and earn more than the workers. France is also the most taxed country in the OECD and most voters are either retired or will retire next decade. It's just another clientelism.