You pay to be a part of a union so it must have some kind of value to the customers (the workers) otherwise no one would pay and there wouldn't be high union me

You pay to be a part of a union so it must have some kind of value to the customers (the workers) otherwise no one would pay and there wouldn't be high union membership. If workers felt that a good attitude and honing their skills would get them paid more than being a part of a union they wouldn't join.