It really is as simple as this:
In the white western world, low birth rates are caused by a combination of female empowerment, careers, high cost of living, low or stagnant wages, and niggers (literally). White foids simply do not want to live around crime ridden nigger areas and a rich white male is the only one that can assure her and their kids, a comfortable life in general and in a decent enough area away from niggers. When white Americans say that they don't feel optimistic about bringing children into this world. They mean that they don't like the high cost of living and niggers.
In the developed East Asian world, low birth rates are literally caused by Asian women not wanting to have ugly full blooded Asian babies with full blooded Asian men. The niggers in essence, are literally the Asian men in that part of the world. In an increasingly globalized world, people see images of other peoples and are conscious about it. We East Asian men are simply repulsive to a lot of East Asian women (even in East Asia) in this increasingly globalized world. And if the conditions are right, the two primary ones being that if the Asian woman is financially independent, and that there are simply no foreign non-Asian races of men nearby, a lot of Asian woman opt out altogether in dating, marriage, or having children and the birth rate plummets. The people literally die off over time.