I think there are jobs where those distinctions don't matter as much, but creative jobs and other areas where the ability of an employee to deliver quality is very personal don't seem to work well with unions in my view.
I would have loved to pay that teacher more because he did so much more and had a huge positive influence on his students, but the union would never have allowed that.
I prefer to be paid 150 than be paid 130 and my colleague 110. It is stupid to have as a goal to earn more than you colleagues. Your goal should be to maximize your own pay.
Divide and rule is nothing new, and playing on the extra individual effort rewards is a very cheap trick to lower the working condition of everyone, possibly even the one doing the extra efforts. It doesn’t take a Nobel price in economy and a certificate of adhesion to Marxism to fathom this basic power dynamic leveraging on sociological imbalance, does it?