That's classic game theory. It'd be better if everyone refuses to defect.
I'm not sure it is in unionisation fights, particularly in an industry as tightly knit as gaming. You're trading a short-term kiss from management for being hated across the industry. That forecloses all kinds of career opportunities outside the majors. In game theory, this sort of repeated interaction is exactly what incentivises cooperation.
We don't know what benefits they received from defecting anyhow