The question is whether you should be able to completely opt out of the public healthcare system and go 100% private. Which IMO you shouldn't be able to - otherwise you get yet more fragmentation and higher costs.
But certainly, most healthcare providers would still be private at least for a good while.
You may be right, but we'll never know how Bernie would have done against Trump. Personally, I think he would have won by a much bigger margin.
Democrats spent a lot of political capital to pass the ACA, and the thanks they got from voters was being kicked out of the majority for almost a decade. The law was unpopular at first, but now that people have gotten used to it, the ACA finally has majority approval. Today, Democrats are back in the majority and one of the major figures in passing the ACA is serving as POTUS, so he sets the agenda, and the agenda is to fortify the bill which is essentially his legacy.
Meanwhile M4A is championed by an Independent senator who isn't even a Democrat. No way Democrats are going to go with his plan, even if it's supported by a majority of their base.
Politics is weird.
Of course, the Republican party will always oppose universal Healthcare. But why does the Democratic party oppose it when the majority of Americans can agree on the specific plan of Medicare for All and much more than the majority of Democrats too?
There must be some reason for the Democrats not to back a generally popular and overwhelmingly popular amongst their base policy that also is generally good for the country and economy, both to reduce inequality and increase economic output, but I just don't see it plainly.