Is this a joke? You're wildly reaching with the definition of both 'efficient' and 'market' on this one.
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.
"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.