It is for the same reason why “Medicare Advantage” plans exist. These plans are operated by private companies using tactics to deny health coverage.

https://www.newsweek.com/how-medicare-advantage-scams-senior...

Expanding, essentially the US has the worst of all possible worlds.

Most provider costs are obscured / complicated by insurers sitting in the middle of transactions.

If they weren't, providers wouldn't do some of the all-but fraudulent coding shenanigans that have become normalized. But overbilling a faceless insurer is fine.

And likewise, patients would have an incentive to shop around for the most cost effective services, instead of no one in the system being able to proactively say how much something would cost until the insurance claim is submitted and processed.

USA Anti-trust is on life support and there is generally very little political willpower to disentrench incumbent capital interests.

Wealthy lobbyists for providers and health insurance companies prevent any change basically.

Also misguided American exceptionalism whereas people think the healthcare standards will go down significantly if there is a public option (as if they weren't already down for the things people can actually afford).

They aren’t.

Doctors in Canada went on strike when nationalized healthcare was pursued by the government in the 60’s.

The government broke the strike by importing foreign doctors.

https://en.m.wikipedia.org/wiki/Saskatchewan_doctors%27_stri...

In those other countries doctors power was significantly curtailed long long ago.