I think so, because he did radicalised and organized a bunch of people and then just led them back to the democratic party who are call by many the "graveyard of social movements" if he would have just broken with the Dems he could have used his huge support and his important allies and supporters to make a socdem labor party.

i always saw Bernie as a failed Obrador, both were socdems ignored by their lib party, but unlike bernie, Obrador was willing to pick fights inside his party until eventually he left and made his own party with his most loyal supporters and now he is the president and his party the dominant one. maybe bernie would not have been as successful but a small labour party you led is better than just being continue to be sideline by the dems and ignored.