Well generally the workers who make these games actually care about the game and want to make a good experience for the players. The execs however, only care about how much money they can make off of the product.
Having a union (assuming that the union is run well),
- ensures a better product for customers
- ensures better working conditions for workers
- ensures better pay and benefits from workers (at least in programming roles, the games industry is generally underpaid compared to developers in other industries)
- provides protections against undue firings and layoffs
I would be curious to know why you don't think a union would be good for these people.