Oh, I agree it won’t be easy, particularly when taking profits from rich people.
I’ve heard it likened to a house full of asbestos. Knock it all down and there’s likely to be collateral damage, but meticulously taking it apart will take a considerable amount of time. I feel it would be easiest for governments to purchase the insurance companies, then slowly amalgamate so it’s all one network open to everyone.
Oh yes, your pay-to-win government duopoly isn’t helping anything, but don’t call it impossible. The Affordable Care Act was a start, and I don’t doubt the right people could make universal healthcare access a real thing in the US.