Comparing us to countries that are hardly as populous as one US state is not a fair comparison.
As anyone in the tech industry should know, there are a lot of unforeseen issues that popup when scaling something. It's rarely as easy as adding more CPUs or more people for that matter.
Healthcare in the US is run at the state level, moreover, in Canada it's also run at the Provincial level.
Germany's healthcare 'system' is bigger than NY and California combined.
In Switzerland, insurance is at the cantonal level.
Scale is not the issue - in fact, scale should mean lower prices.
There actually is not a lot of competition for Medical services in the US, you have very powerful guilds with power handed to them by the gov.
It's almost Mercantilist in a way.
If there is a bottleneck at scale, though, it'd be nice to know what exactly it is.
This also doesn't detract from my broader point that U.S. healthcare seems to intentionally exist in a no mans land.