Paying for a child's room, board, and a reasonable number of gifts costs something like $12,000 a year.
Picking a state more or less at random, Wisconsin's school board spends $13,500 per pupil.
Like most budgets, we can expect the total [child budget] to be fixed. If someone is unnecessarily doubling total cost per child, you should expect total number of children to be halved.
This is exactly what we see.
The market knows.