Probably because California is NOT a right-to-work state, and all studios that matter have agreements with all the unions (guilds) that make their productions u

Probably because California is NOT a right-to-work state, and all studios that matter have agreements with all the unions (guilds) that make their productions union-only jobs. So, even if you are Tom Cruise, Dwayne Johnson, or Scarlett Johansson, you have to join the union in order to get work. * Yes, there are small studios and some other ways of avoiding this if you only want to film in certain states, but if you want to earn the big bucks, you have to join the union.