My experience with unions is that they start out with noble intentions, and then within a generation or two of union leaders devolve into just serving themselves; meanwhile, management suffers with worse and worse employees, because they can't do anything to get rid of the bad apples. Over time, the bad apples bring in more bad apples and things get progressively worse. That can happen in a non-union company, too, but then it'll get punished by the market.
It's really a question of misaligned incentives; the union reps have no incentive to do anything to help the company, and often have incentives to do the exact opposite, like initiate a strike at the worst possible time.
What I don’t get from your comments is why you think unions are bad because they can have bad actors, but are ignoring that the company’s bad behavior doesn’t go away if the union does. And this happens even for well compensated roles. Look at examples like when Apple, google, and a few other companies entered into a cartel agreement to suppress engineer wages.
