that's just the other side of the coin. adulthood means responsibility and reliance on your own resouces. in early XX century children had had work aged 10, married had children etc in late teens. in the middle of XX century one's adulthood was starting after finishing education - early twenties. now people do not get married until in their thirties, have children in late thirties etc. "old age" is not synonymous with "pension age". it is almost impossible to find a proper job when you are 50 y.o. - nobody wants to invest in you.