In 2016 he surely did. That's when the superdelegates were out in full force.

In 2020 it was a much more concentrated backstage effort to hamstring his candidacy, from when they cheated the coin flip between he and Pete, orchestrated an embarrassing debate episode with CNN, and handed out favors to the more popular candidates to drop out and endorse Biden, who was never higher than 5th in popularity, only barely ahead of Mike Bloomberg.

The Dems played dirty. They were sued in court for it and argued that it was their right, publicly.

So, I don't think it's factual to pretend they ever won fair and square.

The irony is that Sanders speaks so eloquently to workers and the poor, and he had widespread support among men, something the Dems have been losing to their detriment since 2008.