I am not a member of a union and I think my wage is pretty good. My position is you would not be able to get good employees if you weren’t paying a sufficient wage to entice them to work there. You may get poor quality workers to work for less, but your product will suffer because of it, as would sales. As such, your wage has to be commensurate with a quality workforce. The old saying, you get what you pay for, applies to many things.
I would also argue the high-quality union workers would likely be making more money if they weren’t limited by the contract, and those problem workers would not be making the same amount of money as the good workers or they would be gone from the company.