Unions can organize without the government having any protections. It’s very difficult to organize that way. It’s difficult to organize even with the most union-friendly government imaginable. But either way, it can be done.

Unions in the US have been shot by police at before. Hard to have less government protection than that.

Your idea is one of the specific reasons many companies try to label everyone as an “independent contractor”. Especially people like voice actors are not “employees”, and thus do not count as such for your idea.