They have the balls to torch cities, kill people and make excuses for the murderers. They live in their own reality; the glorious revolution is happening and any day now, once they've burned enough dumpsters, the government will fall and they can take charge to create a new perfect society.
If the Democrats tell them "enough is enough, sit down and shut up with the intersectional justice stuff, we need your help to win elections" they'll be forced to break away. Otherwise they'll lose what they've invested their entire identity in. Normally I'd agree that forming third parties is something people just idly threaten to do in the future but the Democrats will have to dismantle wokeism to survive, and they don't know how to create anything inspiring to take its place. "Vote for more globalist trade deals!"
The party they create wouldn't be a big party nor capable of winning national elections. There are already local parties like Socialist Alternative in Seattle which Kshama Sawant belongs to. I could see them building a nationwide party incorporating smaller parties like that that can install a few city council members and state reps here and there in deep blue districts. Maybe take a couple House seats .