In the case of many teachers, there is no "company". The union fights valiantly against the State, and against the pay structure Voters democratically select for their public servants.

Further, I posit that existence of such Unions serves as an incentive for voters not to simply assign more pay and benefits to such servants directly. Mayors and Governors know that it's always going to be a "Union game" and all they can do is negotiate - even when they're Progressives who actually want to pay teachers well.

It just gets worse when it's Cops instead of State School teachers.

Big assumption about "interests" lead to bad analysis, in my experience.