A lot of people feel that broad welcome in a policy means fewer resources to share with more people. If you're in an advantaged position, it may make sense to oppose such broad social care measures.
Yet most of those countries have cheaper/better/cheaper and better health outcomes.
'The supply of doctors is constrained' is largely a red herring.
This doesn't explain the disproportionate costs of decades-old medications and procedures still using decades-old methods.
You can maybe justify high drug costs based on that, but drug costs are a small fraction of overall medical costs.
Note in not saying this is ethically fair or optimal, just that it’s a consequence of the particular system
Your theory does not explain why the other 86% is so bloated.
Beyond that, you may be conflating prescription costs with drug research, which is not the same. The fact that prescription costs take up roughly the same percentage of total healthcare costs seems to support my point. An equal percentage of a bigger pie would indicate they are inflated.
My personal stance is that the US optimized for access and quality at the expense of cost. As the saying goes, you can only have two. R&D spending is a large part of this. The US contributes over 40% of the worlds medical R&D, effectively subsidizing other nations. It’s not a bad thing and it doesn’t explain away all healthcare costs but it does create systemic ramifications. It’s been awhile since I’ve viewed the numbers, but the US had the highest health access and quality scores for a country of comparable size. Off the top of my head, I think the next closest was Russia. Again, the point being simple comparisons are harder than one may think when dealing with complex systems.
I keep harping on drug prices, because you keep mentioning R&D. R&D is not the reason for why non-drug healthcare is so expensive. There is no mechanism by which high R&D costs lead to high specialist/GP/nursing/administration costs. There's no way for, say, Pfizer to siphon money from any of that into R&D. R&D is not the reason for why these costs are so high.
Related to your comment about the difficulties in comparison, you underscored my other point. People flippantly say “but look at country X’s costs” without understanding the nuances that make such comparisons worthless.