1) Any union employee can still be terminated with minimal documentation demonstrating incompetency or any other issue. All you have to do to fire someone in a union is take notes that they failed in their job duties, email them about it, take notes that they didn't improve. Unions cannot prevent you from firing workers for cause. The vast majority of "benefits" teachers unions in the US provide is a phone number for a lawyer. If you can't convince a judge someone should have been fired, why are you paid anything at all?

2) The fact that the administration does not do the above is because there are zero teachers to replace them with, because nobody wants to be a teacher. They also don't do the above because they are woefully incompetent and utterly incapable of telling you which teachers are good teachers. Note that, no, students aren't good at telling you who are good teachers either. Administration and students alike often love teachers who are wildly incompetent and don't do their job, and just as often hate very competent teachers who aren't willing to jump when they say so.

3) The administration is incompetent and unable to fire teachers based on merit because they are politicians, not educators. They weren't hired for their competency as an educator, or skills as a manager, or experience dealing with children, but because they have enough clout in the small community to parlay that into a $250k a year job where he wastes taxpayer dollars on absurd projects. Property taxes are less than half one school district over, and their system isn't any more competent.

If an administrator is unwilling to do the paperwork necessary to do their job, like fire someone who has union backing, means they should not be in administration, a job defined by paperwork. They get paid that insane sum of money to administrate a school district that has 500 kids in 3 schools which already all have their own administration staff. Meanwhile, they utterly refuse to support teachers trying to keep problem students (you know, that thing everyone always hates for holding their kids back and wasting everyone's classroom time) out of the way, and consistently bow to parental pressure to not punish misbehaving students because their job is political. Teachers want to get rid of misbehaving assholes, but the administration does not put in any effort to do so.

This is all because every rural small town in America is dying. Anyone with any financial literacy, capability, or valuable skill ran away. All that's left are the people who had no life plan, who flunked out, who wasted their youth, and have not grown up emotionally from their highschool days. They coalesce and form your local "good ol boy" network, and tend to take over local politics.

This superintendent had the job for decades despite continuing decline in outcomes. Hows that for not firing underperformers?