The kids could have won the Sburb without Vriska's interference. She fucked the kids' session up when she put John to sleep while Jade was trying to shoot her Cruxite Artifact

Yeah of course she did- But also Bec Noir was already in their Session, fucking up the Planets and heading for the Genesis Frog. All Vriska would have done by NOT being a meddlesome 8astard is create a Doomed Timeline. If the Kids merely won, there wouldn’t be a Scratch, and without a Scratch there would’ve not been an Alpha Session, which in turn would mean no Alpha Kids. Which means no interaction for Calliope and Caliborn, if they even existed in the new Universe made by the Beta Session, and it would also mean no origin for the title of Lord English, no battle in the Masterpiece, no ARquius to get absorbed into Lil Cal, and no Black Hole bringing the Juju Breaker to Caliborn. They required to fail the Session and Scratch it for it to be the Alpha Timeline, and not end up doomed and dead.