We're talking about two separate issues here. The public could've sent a clear message about what its priorities are this cycle - and they did
They voted in 40 extra Dems in the house to act as an oversight check on Trump. They did not vote in 40 new Dems to advance medicare for all. We know this because many of the people running weren’t running on it. The issue of the Dem establishment attempting to squash x or y policy is somewhat of a moot point since any person can run for a Dem congressional seat by championing whatever policy they see fit. Pelosi and Schumer or any anti healthcare lobbying effort don't have any influence over whether someone on the outside of government chooses to run for congress. Therefore the argument that the Dem power structure isn't allowing universal healthcare to move forward doesn't hold much water, since its the general public who are still the ultimate arbiters in this regard, and they spoke fairly loudly two weeks ago that they want a check on Trump and more women involved in Congress. That's about all that came out of the election in terms of mandates. There was very little conversation about universal healthcare, single payer, medicare for all or whatever we want to call it. That suggests that the national conversation about proceeding down that path is incomplete and still needs to be developed in a much stronger way than it has at a grass roots level.
First its incorrect for you to presume that all voters that voted for candidates did so solely to "act as an oversight check on Trump". In fact of all the focus groups where I talked to people literally none of them said they were voting for a candidate because "act as oversight on Trump". You are just making that up as
the reason that people voted with no supporting evidence.
Second, its incorrect to repeat the establishment lies that not many candidates ran on Medicare for All or it wasn't discussed. I heard it brought up in almost every debate I listened to and if you actually look at the numbers the Medicare for All caucus is growing. No one voted for Ocasio-Cortez solely to "act as oversight on Trump". By your logic, just because no one challenged the well funded establishment golden boy Adam Schiff from the left this time that somehow means his district does not care about universal healthcare. That's just bonkers. It's just not accurate at all. Also its plainly false to suggest Pelosi and Schumer have no influence over candidates when they clearly do and they control the purse strings. Its an uphill fight for any universal healthcare candidate because its not what the Dem leadership wants to push.
Its a process for opinions that are popular at the grassroots to try to find their way to the establishment in power. That process has begun and we are already seeing idea of universal healthcare much stronger in popularity than it was 5 or 10 years ago. That process is going to continue. The fact its not complete yet is not proof that somehow the polling is wrong here. On this issue the polling only scratches the surface. Support is stronger even than polling suggests. Beto destroyed every fundraising record for the Senate without corporate PAC money and his stalwart championing of universal healthcare was clearly a big reason why. I donated to Beto not so he could "act as oversight to Trump". I donated to Beto because he steadfastly refused to back down on his support for Universal healthcare. Its pretty much why everyone I know who donated a fiver did so. So to downplay the fact the greatest Democrat fundraiser of all time was a universal healthcare supporter and not accepting corporate money is just repeating the propaganda the ad hoc alliance wants you to repeat.
It certainly was part of the national conversation despite the fact that Democrat corporate media and many establishment candidates intentionally tried to downplay it and the
ad hoc alliance of private health interests have been doing everything in their power to stifle any conversation on universal healthcare. Trump had to write an op-ed attacking it. Whenever I was driving in the two weeks before the election I was listening to Rush, Hannity, Prager, Medved and that whole roster of right wing talk radio constantly bashing universal healthcare every single day. If you don't think it was in the national conversation then you simply weren't paying attention. Its very clear that both Republicans and the ad hoc alliance of private health interests are deathly afraid of a public option and they are doing everything they possibly can to twist the conversation away from it because they know it has massive grass roots appeal. That's why they spend hours and hours on end in the two weeks trying to attack the concept from every imaginable angle.
The reality is there is a heavily funded organized effort by an ad hoc alliance of private health interests combined with corporate Democrats that really don't give two fecks more about what the public wants than the Republicans.
An organized coalition of politicians at the state, local and national level combined with representatives of the stakeholders interested in universal healthcare is just in the embryonic stages of development. That's whats going to be needed to force universal healthcare into the media conversation because you have rich, powerful special interests with closer ties to the corporate media that don't want it.