The US government is involved in ways that make it inefficient. For example, I don't get to choose my insurance, the government has ensured that instead my company does for me. While I can in theory get insurance elsewhere I lose a large subsidy in doing so, no insurance I can buy can possibly be a better deal for me, even the company insurance is bad.
The incentives for insurance are to ensure that I don't quit, not that it is good healthcare or a good deal.
I don't know what my company pays for my insurance, but if I opt out of that insurance that money is lost. I know I pay $100/month (not the real number but close), and plans on the government health market start at $800/month (after the tax credit), plus by using the company plan they kick in another $100/month in a HSA match, and HSA money is a tax advantaged investment (AFAIK you can only get in an HSA from your employer). So by using my companies insurance it is like getting an additional $800/month in income (some of which is invested!).
I didn't look into details of the insurance market plans, but there were 40 different plans available there for me to choose from (as opposed to the 2 my companies gives me). I suspect that something similar to my work plan is more expensive than the one I listed above. I also suspect that if I was to look at all 40 plans I would choose something that wasn't not similar to the choices I have now. However with the amount of money I'd lose it isn't worth my time to examine my options.
WWII Wage Freezes is where it started, the government regulated that employers could not raise wages so employers started offering services to attract talent, in those days it was having a doctor on site at the factory, or office that employees and there families could see for free.
years later that transitioned to comprehensive benefits packages
The incentives for insurance are to ensure that I don't quit, not that it is good healthcare or a good deal.