Most schools are reasonable. If you were to divide the budget by the number of students, one would find the “real” tuition is lower but that the higher rate means those who can pay end up subsidize those who can’t (same system used by colleges).
But also remember we are running am expensively complex school system (basically double of what the goyim spend) without endowments, without government subsidies and in spite of the fact that very frum Jews can hope for the hoigh incomes that our secular cousins earn.