Yet they have the SAG-AFTRA union which had a strike to force better working conditions from games companies.
https://en.m.wikipedia.org/wiki/2016–17_video_game_voice_act...
Further acting is older than gaming, and those unions were given space to form during a period of time that was very different from today.
The concept is similar, the volume of people is vastly different, however.
There's nothing particularly unusual about game dev jobs or companies compared to other areas of tech (especially including startups); it's just that there are a lot of people who want to work on games. It's been that way for at least a couple of decades now.