It would be great if benefits unions are known for fighting for like health care was guaranteed by the government, but there's some things that a union closer to the workers, which is focused on one thing, can better fight for than the government, like standards for safety beyond OSHA, standards for scheduling, training, discipline, etc. If I understand what you're saying right.
If you think unions are a smaller extra government entity, how do you view Apple in that same lens? Likely, the unions have the least power in this triangle (besides individual employees not covered by a union), and Apple has more power than the government in some, but not all, respects.