Maha makes a very good point about Democrats (boldface mine):
Of course in a democratic system everybody has to compromise. That’s not the issue. The issue for Democrats is that we’ve gotten way too good at compromising with ourselves. We don’t propose what we actually want and then get as much as we can through compromise. We deny even to ourselves what we really want and then propose things we don’t want but which are less awful than what we fear the Right will force us to do.
The clearest example of this was back in 2013 when President Obama’s budget included cuts to Social Security and Medicare. This was part of a “grand bargain” meant to appease the Right from completely trashing the country. Fortunately, the grand bargain fell through, and the Right failed to do as much damage as they’d threatened.
The Affordable Care Act was the most progressive legislation passed by Congress since the LBJ Administration. Even that wasn’t what we wanted, although I supported it because I thought it was the best we were going to get, and people were dying from lack of health care.
But there’s no reason Democrats can’t be trying to make the case to the people for single payer. There’s a great case to be made for it that people never hear, because only a few renegades like Michael Moore ever make it. If the people become sold on it, it can happen. That’s how Reaganism took over, you know; the Reaganites persuaded the people that tax and budget cuts were the road to the good life for everybody.
Where were the counter-arguments? Yes, by the 1980s the Republican Noise Machine was doing a great job of drowning out dissenting voices. But the Republican Party is imploding now. The Noise Machine is arguing with itself these days…
There’s also a difference between necessary incrementalism and plain old foot-dragging. The Dems are a party of foot-draggers, IMO, for a lot of reasons I want to write about later.
I think the moderate left of the Democratic Party is too timid. But, as Maha notes, there’s another wing which simply does not want these things.
Just as we learned in the 1990s, when Bill Clinton (with an assist from Hillary) engaged in racial stereotyping, there is a significant fraction of Democratic voters who are, let’s say, less than progressive when it comes to race.
But the Northern Strategy also shows there is another segment of the Democratic Party that does not care about those who aren’t at least middle class (and isn’t particularly fond of them either, especially if they don’t have a college degree). Nor is this an omission: it is intentional policy.
It’s foot dragging in an attempt to stall or prevent the solidarity the left needs.

Here in Canada some of our more progressive Progressives put forward the ‘Leap Manifesto’ to start a conversation on a way forward that would honour the basic values of all Canadians… well, the feces met the fan at such a high velocity. And that was just from other progressives. The right went into their usual ‘sky-is-falling’ act.
https://leapmanifesto.org/en/the-leap-manifesto/