So why aren't the ones who get money from upk passing the savings to us?
Lol, you gotta ask them that.
I'm curious whether this is only happening at schools that have a full K-8 program after UPK, or even at pre-school only programs. If it's a pre-school only program that's literally pocketing the UPK money, that's absolutely indefensible, and the parents should boycott that school. If it's a regular Yeshiva with a pre-school program, I'm not defending the practice in any way, but I can see where they might be tempted to keep charging regular tuition and use the UPK funds to essentially subsidize other parts of the school.
Bottom line is, these schools will be influenced by parents' decisions. If parents organized and stood up to the school on this issue, you can be sure things will change. Or if everyone flocks to the few places that are charging a reasonable, reduced tuition, that will cause the remaining UPK schools to change as well.