A lot of Democrats have kind of "left the building."
With the Democrats finally in total control, this was going to be the Great Progressive Leap Forward.
We'd bail out on all the wars, nationalize health care, run America on windmills, give the rich their comeuppance, and finally accomplish every other leftist goal we've been hearing about since the late 60s. It hasn't worked out that way, and it's easier for them to just keep plowing ahead with their heads down, repeating the rhetoric, than figure out what to do out in the real world.