It interacts badly with insurance being offered as workplace benefit. If you quit or lose your job, you'd lose your health insurance. And any plan you signed up for after that would then treat you as "pre-existing embers" and expect you to pay accordingly. The bundling of health insurance with workplace seems like the healthcare original sin to me.
Obama couldn't change that, so the ACA redesigned the system to work with it. Despite being called insurance, health insurance is no longer really viewed or designed to be any kind of insurance. Instead, it's supposed to be Netflix for healthcare. You pay a flat rate, and then get unlimited healthcare. Obviously, the issue with this is that if you don't need healthcare you can just not sign up for the subscription. So the ACA tried to solve this by requiring everyone to sign up. Once everyone is required to sign up, it's not right to discriminate against preexisting conditions. It may not be an especially good system, but it is coherent.
The US is allergic to taxes. Maybe it's a marketing thing. Benefits paid for by society.
Maybe a department of Return on Investment. See what those taxes pay for. Contrast to buying private versions of the services at the same SLA or better.
It’s more that the US is more like a collection of 50 little countries, and it’s supposed to be hard to accomplish much at a federal level. That separation has eroded a bit in the last 50 years but it’s still very much a part of our political ideology.