I know all of this has been said before, but fuck it:
At the end of the day, he just didn't have it in him to go as hard against the establishment Dems as he needed to.
I think the propaganda got to him and he genuinely believes it was his fault that Trump won in 2016 and desperately doesn't want to be blamed again (Even tho he totally will be no matter what he says or does).
What we ideally need is basically a leftist version of Trump (As in not prejudiced, but with the same shameless, boisterous, don't-give-a-fuck attitude).
It's a difficult way to move because a lot of the popularity of these two figures was explicitly because of the compassion they held for basically everyone.
you can be compassionate with the working class you want to represent and ruthless with everyone else