> classic game theory

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.

As long as someone knows that they're going away from the industry good it's enough for a single defection.

Humans have the ability to consider things beyond their immediate incentives. Most find it difficult not to.

We don't know what benefits they received from defecting anyhow