This is what I'd consider the "traditional" answer to the function of a union. I think it makes plenty of sense. The parent comment seemed to me to suggest tha

This is what I'd consider the "traditional" answer to the function of a union. I think it makes plenty of sense. The parent comment seemed to me to suggest that a union would both keep the door open and the price high, and I don't see any clear way a union would do that.