Trust me it doesn’t work perfectly in other countries. Yes, americas system is messed up but in countries like Sweden you will still have to navigate the system to actually get the healthcare you need. There are people who are denied healthcare in Sweden because the govt has deemed that it’s too expensive to save them (while people with similar conditions and a good insurance in the US are covered).

Also inflexibility, large backlogs, quality of staff, etc.

In Canada all of our best doctors go to the US and there's often nurse shortages. It's not just a private incentive either, the US gov pays out far more in public healthcare coverage as a percentage of GDP and per capita than Canada and almost all of Europe.

Despite their reputation the US doesn't have a lack of public healthcare spending (ranking #1-3 in the world). It's just their system's insurance regulation is extremely convoluted, creating risky edge-cases and perverse incentives. If they fixed that they would by far have the best healthcare system in the world.