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.