through gerrymandering, housing prices, and use of police getting rid of groups they consider 'undesirable', most notably the homeless, it is possible and unfortunately has been achieved by some dems that their localities contain mostly just people who have no complaints about their reps choices.
the problem dems run into is that this is not at all possible nationally, and it can't be achieved in EVERY locality. this doesn't stop them from trying, however. NYC really feels like dem elites constantly pissed they haven't been able to get the San Francisco result despite everything.
i don't think they want to lose, but they sure don't want to win in a way that involves having to even pretend to listen to much of their actual base. its been the M.O. since the new dems. casting off the 'special interest groups' that ask them to do shit at all has been priority number 1.
just like how their main takeaway from Obama's election is to never let anyone jump the line, all they learned from his years in office is to never promise anybody anything