I supported Bernie and supported his health care initiative. Whether you believe Bernie was cheated or Bernie lost the primary or something in between, fact is, Bernie later on supported Hillary for prez. He did so for pragmatic reasons.
Obama/Hillary would not take on the insurance lobby. For pragmatic reasons. If you recall, Clinton's early debacle in his attempt to enact universal healthcare in 1993 pretty much stalled out when the public didn't support it. It helped bring in the Gingrich's GOP congress and threatened the Clinton run for re-election in 1996. What makes you think things would be different for public support for universal coverage 20 years later?
Result was nothing done between 1993 and 2010 until the ACA, a pragmatic weird hybrid that satisfied nobody it seems but did good for many millions of people. I saw the ACA as a bridge to universal healthcare which is why I'm not surprised at conservative's antipathy to it. What I don't understand is antipathy from the left. Or this idea as you say, by just holding out for universal healthcare coverage the american people will have a change of heart. That didn't work 1993, what was different in 2009, when this country was in a terrible recession and the last thing people wanted to consider was a new expansion in government programs.
Maybe Trump will break the system so badly that universal coverage will be the only reasonable fix. To people with the means to ride out a disaster like that, maybe this is acceptable.