I think it’s because there’s some unwritten rule about not inducing children to commit suicide. I don’t think a little kid could handle such a curriculum without getting severely depressed and offing themselves. Adult survival of this is much higher, mostly thanks to access to sex, drugs, and rock and roll, something children are not allowed to have access to, given local laws and their status as legal minors. It is correct to lie to them and make them think that if they are good students now they will be successful as adults because they are too young to be exposed to night clubs where 9 to fivers tend to find refuge and a drug dealer at the end of a tough shift to survive and avoid suicide.