If I am not mistaken, there were still 70+ percent of all Americans that supported universal healthcare as of 2020.
If you ask a Democrat about whether they support socialized healthcare, they'll tell you that they of course support "universal access."
What is "universal healthcare" anyway? It sounds like some the kind of intensely workshopped and whiteboarded meaningless marriage between socialized healthcare and "universal access" that "Medicare for All" was designed to head off.
I think the Democrats correctly recognize that there is not a deep belief in the idea that of socialized universal healthcare in America. In the survey you quoted, I would bet that about 20-30 out of that 70% support the effects of it (i.e. universal free or cheap healthcare), but would not support a tax increase to pay for it if needed.
Regulate pharma pricing, cut the insurance companies as middlemen (they make $10's of billion in profit and their CEOs get paid millions), and make medical school affordable, even subsidize it if necessary.
All of these issues we can sit here and discuss for hours have solutions, change will only happen when we all agree that healthcare is a human right, and shouldn't be tied to a job.
"It's a matter of creating a sound plan" is not the trivial thing you make it out to be without having a broad mandate about healthcare. You sound like the typical person who has never run for political office, but somehow thinks that they would totally fix the system if they were in charge.
Governments are an efficient market of sorts. Affecting the market needs either broad changes in society's point of view, or catastrophic events. It's indicative of the magnitude of conservative thought in American society that even the worst pandemic in US history did not result in a bipartisan push towards socialized healthcare.
For what it's worth – I agree with you about healthcare being a human right, but I'm not the person you need to convince. It's the people in your nearest conservative-leaning district who tend to treat healthcare more like going to the car dealership.
Similar, if OP thinks that there is an obvious case that Americans would back a completely socialized healthcare system, they are probably wrong, and the politicians that actually spend all their time talking to people and understanding the "market" of votes are probably right. One survey quoting a number of 70% does not mean anything particularly significant.
The problem with healthcare as a market is that it isn’t. We don’t allow medical professionals to decide that you don’t deserve blood pressure medication. But we do let bean counters decide that you get to die for lack of resources.
By doing this not only have we created a moral dystopia, but we’re wasting resources that we supposedly care about.