Russian and China are both mixed bags. Russia has a well-educated, literate population; is technogically advanced in many areas; and is recovering economically from the vestiges of communism. China still represses its people politically but has moved quite a distance from its economically repressive Maoist past. Scientific knowledge is available in most areas of the world as modern communications bypass barriers. So even in many poor and underdeveloped countries the birth rates are now dropping below replacement levels, following the lead of the most advanced nations.
So my comments about how to raise the birth rate were made sarcastically rather than seriously. With the possible exception of Islamic nations, the world is not likely to revert to barbarism.