The problem with the system in the USA is that paperwork can make all the different in costs. The burden is on the individual to comprehend all the implications of their choices. These choices are beyond do I want my ailments addressed.
You could provide every American with extremely robust healthcare for a trillion dollars a year. Probably less as you allocated resources based on need.
We choose to spend that on the military. Basically you can choose guns or butter, we choose guns and empire. Whether that is a “correct” decision is an exercise for the reader.
You could argue for lower defense spending, but there’s a hard lower limit (which is unknown) and if you cross that threshold, the world changes for the worse very quickly.
The rules-based order is underpinned by tanks and planes and nukes. Diplomacy is a layer of abstraction over violence and potential violence.
Medicare costs $800 billion/year and only
covers 20% of the population. They are on average the most expensive 20%, but I doubt you’re going to cover all the rest for another $200 billion.
Often, people in situations where they require healthcare are least able to assess the implications of their choices, as well. It is very literally praying on the sick.