But it is. Why do you think it takes 10 years to join the longshoreman's union? Why do you think they make $140,000-$400,000 a year doing menial lower skill work? Why do you think it takes well over a year to join the plumbers union in some states?

They are making their money at the expense of non-union workers. There is no value-add in banding together to make more money. It's the exact same concept as the non-poaching rules in tech. Cartels advantage the cartel members at the expense of the everyone who isn't in the cartel, and unions are a cartel. They restrict supply of a product (labor) to increase the price at which is it sold. Cartels are bad when OPEC does it, and they're bad when the UAW does it.

Exactly this. But the same dynamics apply to all unions including the ever sacred teacher unions. Their playbook is to use children as a rallying cry for continual pay increases, resistance to performance measurement, and resistance to competition from charter schools or any model that allows school choice.