Obama floated a single-payer option for healthcare, he was stopped by Republicans.
You might want to check that one out again. The Ds had a majority in Congress and managed to fuck themselves on that one.
Single payer will never pass, big insurance owns too many congress people on both sides of the isle. A couple million dollar payoff for a dissenting vote is much cheaper than the billions they’d lose if either ACA is repealed, or we cut them out of the game with something like universal healthcare.