We've unwound industries before - if we have the political will we can do amazing things.
But the people in and using those industries have no desire to change so anything that does happen is likely to occur slowly from expansion - e.g, bringing Medicare to earlier and more people, and expand children coverage, etc.
Those are probably the easiest levels for simplification, but I'd expect significant pushback anyway. Something like start medicare at 55 would be a huge difference to most providers, just due to changes in reimbursement.
I think there's some significant evidence that "users" of the private healthcare industry are actually quite unhappy about it. Due to some structural quirks of the US, it seems like it's less about how many people are happy or unhappy and more about how many dollars are spent in favor or opposition of a change.