Totally different circumstance because the population pyramid even after black death looked great. Tons of incoming young people every generation. In fact it im

Totally different circumstance because the population pyramid even after black death looked great. Tons of incoming young people every generation. In fact it improved the pyramid! The black plague disproportionately killed old people. This is going to end up in a top heavy pyramid with a ton of old people relying on fewer and fewer young people. Simply because fewer and fewer are being born every year.