The thing about Bernie in 2016 was that he tapped into the very real frustration, especially among the younger generation, that there was an essential unfairness about our society and that the system was rigged against the everyday Joe. His popularity was never really about socialism.
It's completely over for him now. He's clearly sold out to the system and become part of the ruling class, no matter how much he tries to spin it otherwise.
The good news is that our current POTUS actually IS fighting for ALL Americans.