It's not really a fundamental truth. Everyone's perspective is different. I'm sure I'm not the only one who would rather die than relive their childhood.
It is not necessarily easy to be a child! Heck, I'm 13 and life is most certainly not easy for me, and I live in a place where I get good education and healthcare. In today's modern society, kids are getting smarter but society isn't necessarily getting better. Well, I'm finished with my rant, now.