Why are Hollywood Unions Powerful?

Glen Whitman asks a good question, Why are unions so powerful in the entertainment industry when unions
are generally weak and in decline in most other sectors of the economy?  (Tyler asked the same question several years ago.)

I went to the family expert, my brother the movie producer and he had this to say:

…unlike in most other unionized industries, it’s the INDIVIDUAL members of the unions in the entertainment industry that the management / owners want to work with. For example, Tom Cruise is a member of SAG, (I use him as an obvious example, but every other known actor is as well) and if the studios and producers want to make a film with Mr Cruise, and we all do, we have to come to terms with SAG. Similarly, Steven Spielberg is a member of the DGA, same issue. Though writers are not household names, it’s the same issue, there are specific individuals who the studios want to be writing their TV shows and screenplays.  It  doesn’t matter if Joe or John or Mary is stacking the boxes, flipping the burgers or ringing the cash registers so management can easily hire a non-union member to do the same job, in the film business we need to work with specific individuals who happen to be union members. Thus the power of those (comparatively) few empowers them all.

Combine with a bit of Hollywood leftism and the fact that the big names don’t lose much from unions and you have a very powerful cartel.  About the only way to break the cartel would be to turn the big names into owners – this has been done a few times but the stars earn so much anyway that even then the incentives to deviate are small.  You Tube can give is a
parade of amateurs but as soon as the amateurs become stars this
model suggests that they will be co-opted into the union framework.  Like my brother, I don’t see the power of Hollywood unions ending anytime soon.