I think hidden biological mechanisms related to overpopulation have kicked in. Perhaps, subconsciously, when we see a lot more really old people living around, something switches on suggesting that reproduction can wait. Maybe informational explosion make us wait longer to acquire necessary amount of knowledge, necessary for decent life.

Also, stupid TV and internet entertainment, combined with lack of opportunity in USA contributes to this problem. ... Every time I switch on American TV, I want to throw up.