SJS-
I think what you mean is that there could be enough money to go around, not that there is. Reducing vacations and fanciness of cars and clothes (the “spending” luxuries) of the non-full-tuition families is not going to be enough to bring most of those people to full-tuition level (unless you are very cynical). The “earning” side of the equation on your list is Kollel and SAHM, in each case the difference is a full income, which is much more likely to cover any deficiency in tuition.
The question is if anyone has plaitzes big enough to address this issue.