Where have all the people gone?

 

Styx says that it isn´t a great mystery why birth rates are falling. I disagree. Birth rates are falling all over the world. I assume #MeToo or feminism doesn´t exist in, say, Niger? The cause of the demographic crisis must be global. None of the factors he mentions fits the bill, not even overcrowding. Many "Third World" nations are clearly more overcrowded than the Western ones, yet their birth rates (while falling) are still above replacement level. Again: Niger. 

I admit I have no idea why the birth rates are falling, including in areas where they "shouldn´t". It´s almost as if the Moon does eat people, or something.