You have hit on the most important point here. If all the teachers are bad teachers, then this only protects them. It relocates the problem, it doesn't solve it.
That sort of thing happens on my side of the country all too often.
And if it isn’t a protective transfer, it’s active stonewaling by the school board.
Like Middletown NY did with Robert Sigler.
They first tried to stonewall, then they tried to silence a whistle blower, then they finally admitted that they knew what was going on and did nothing..
..and Sigler was the superintendant of schools in Middletown NY.