Respectfully, you are delusional.

Sorry, but your are just, bold wrong. The so called "capitalist world" has by far the greates wealth and possibilities than any other area of the world. And perhaps that partly caused the drop of birthrates world wide.

The idea that bad conditions let birth rates drop is straight up false. The idea will be disproved by the fact that some of the most poor regions of the world have still high birth rates.

Maybe, the problem is far more sophisticated and all, but many things around there are wishful thinking.