Your hypothetical is interesting, but it doesn't accord with the reasons these workers organized. They did not conceive of the issue as primarily about multiplying all worker compensation by some large factor (e.g. 2x). While they were certainly fighting for higher pay, it was as much about the arbitrariness of career paths as anything. Sexual harassment, crunch time, and layoff cycles were all problems they sought to address.

https://en.wikipedia.org/wiki/Activision_Blizzard_worker_org...

Regarding your hypothetical, two points. First, Hollywood unions did essentially go down the path you imagine. The solution there was to create a less arbitrary system that allowed actors to work their way into the union and get a degree of income stability and protection from (previously horrendous) employer abuse.

"The supply of jobs won't magically increase (it would likely decrease with higher wages)"

You should look into the economics of these game studios a bit more. The unit economics are not like those of producing bricks which an essentially linear (capital, labor) -> bricks production function. The distributive effects between the employers, workers, and consumers would be very difficult to model. You can't really figure out the marginal contribution of the factors of production. To use a Hollywood analogy: Do we know how much less one of George Clooney's films would net if a different actor were cast instead of him? If we can't be sure, can we know what his marginal contribution was?