Of course the parents should do their part, but considering how many hours a day a child spends in school, and how they develop relationships with rebbeim, there is a good chance rebbeim could have more influence on the child than the parents.
I’m not even putting the onus on the rebbeim, but they certainly can incorporate middos and other values into their day, don’t you agree?
Somehow, I don’t think parents are encouraging their kids to buy things they can’t afford, so not sure I understand your apple point.