The recent election showed that the "Progressive" agenda such as "Medicare for All," the "Green New Deal," or "Defund the Police" are not widely supported outside some communities of color and extreme liberal communities.
The Democrats inability to win the Senate and even maintain their advantage in the House shows that most middle-class communities are uncomfortable with these proposals and many people in such communities simply oppose these proposals.
It is understandable, for example, that a community where relatively few people have private health insurance would support "Medicare for All," while a community in which most people have private health insurance would oppose it.
Similarly, "Defund the Police" has support in a community which looks on the police as antagonists ("the Man"), while a community which looks at the police as security are understandably frightened by the suggestion.
If the Democratic party ever hopes to have a working majority in the House and Senate, they will need to support candidates (like President-elect Biden) who have a broader appeal than "the Squad," or people like Senators Elizabeth Warren and Bernie Sanders.