Some avenues require you to sell a specific amount of tickets, and if you can't will straight up cancel it and never work with you again, because it's easier to close a hall and don't make staff work that day, than offloading expenses on you and trying to get them out of you later. With how miserable their sales were, this seems most likely scenario for now. And this "minimal amount" could be 70%

don't you like event organizers
They still hold a panel (unless they announce it's cancelled as well in a week) so the event as a whole dropping them is unlikely