> there isn't enough demand for all that labor to be valuable at/above market-average.
This argument would be stronger if the game industry didn't also feature a large number of insanely well paid executives.
Unionization in the game industry is not about magically thinking that higher salaries will appear out of thin air. It's about low-ranking employees coordinating with each other to correct some of the power imbalance versus executives so that rank and file can get a larger share of the pie.