[bpt3]

What I meant is that something like SAG-AFTRA provides some benefits and sets minimum standards for a work environment but does not limit your ability to negotiate a higher rate for your work, does not require promotion (whatever that would mean in this context) based on seniority, etc.

In the US, doctors, lawyers, and to some extent professional engineers and other licensed professions operate under a somewhat similar model in that they restrict supply of that class of labor through some sort of accreditation, apply minimum standards for the profession, and otherwise stay out of your business for the most part.