Unions tend to use otherwise arbitrary criteria to determine a members value. Not all people with the same number of years of experience, the same job title or the same degree provide equal value to the company.

As a school board member, I had to deal with the situation of a nationally recognized(awarded) teacher who got paid the same as every other teacher with the same degree and years in district. When asked why we wouldn't pay him what he is worth, the answer was simple, your union won't let us. Not every job type/environment make sense to have a union.