It's complicated because issue polling is only so useful, given how many different ways questions can be framed, and "issues" themselves are poorly understood. "Universal health care" is popular. But when you get into the weeds of what that actually entails, Republican messaging is very effective at diminishing its support.
We're all having different conversations here. I fully agree with bozo that voters don't vote for policies, they vote for candidates. Your post i was responding to was arguing that Dems aren't sufficiently reorienting around popular policies due to interference from "The Groups." I think The Groups interfere in harmful ways, but that the electoral impact of that interference is pretty minimal and that the biggest problem, The Problem as I've described it, would remain and things wouldn't look much difference in a week if all of The Groups disappeared completely from this plane of reality tomorrow.
What's frustrating is that the solution to The Problem is fairly simple (not easy and it will take an extended period of time to really show results, but it is simple). Hell, we've seen the GOP do it already. Dems need to bully the media and begin standing up their own partisan media alternatives. We've seen it work, and I don't mean just on Republican base voters. It has worked incredibly well for the GOP on mainstream media editors and producers and the "centrist" voters and even center-left that listen to them. It works just the same way working the refs does in sports. Unfortunately, too many Democratic officials still feel constrained by shitty consultants, norms, collegiality, etc. to even consider working the refs.