[StudentStuff]

It seems your mis-understanding what a union is, the union will talk with management, forming an agreement as to what the pay scales are, how much paid leave is given at minimum, and escalation processes like grieving an issue when management does shitty things to the workers.

The "overhead" you speak of is to pay someone to negotiate on the workers behalf, save up for a strike stipend, and provide worker training (usually Unions will run or subsidize courses to help workers skill up, get licensed, etc).

[solidasparagus]

And now you have a fixed payscale that could easily make it harder to hire.