But what do you think happens to a teacher who keeps driving away paying customers because they have behavior problem children?
If the school is highly sought after in a high demand area then yes - they can effortlessly tell bad parents of bad children to take their money and go.
If the school is moderately sought after in a moderate demand area - and where you are offering a product that the government is giving away for ‘free’ - the economic reality is not so forgiving.
I have seen several “auditorium” parents - and it seems they WOULD rather buy a new auditorium for the school than to admit that their child is less than perfect and might need additional parenting and possibly even (gasp!) discipline.
The system's faults mirror those of life/humanity in general and, as such, have numerous remedies available to those who find their particular situation unacceptable.
Which, of course, makes it infinitely preferable to the current publically-funded version, from which none of us can escape.