Those who can afford to pay more are mostly doing so, through donations.
The majority of everybody else would have to take out a second mortgage to pay another 2k for 5+ kids for the next 10 years if they are even paying the current 4-5k per kid for elementary school and 8-10k for high school.
A family of 8 kids, 2 in Mesivta and 6 in elementary school, is be paying 35-45k. Most people can’t even afford that. The numbers sky rocket once the kids start going to E”Y. So raising tuition probably won’t make much of an effect on money actually collected.