I guess what I'm really getting at is, how unshakable do view this trend in cultural reproduction?

This view requires the continuation of two trends that were ignited with the Industrial Revolution (which caused the demograhic transition), that being: more energy, and longer lives. These two features fundamentally rupture human life history - and I'm arguing that it is all part of a fourth major primate life history transition (in my view particularly, I view this as one massive transition out of the animal kingdom, but that is for another paper).

So, if we get abundant energy globally (which is unlikely short-term, but likely between 2050-2075), and if we extend our life expectancy beyond 80 (which is likely before 2050), than we will see cultural reproduction come to pre-dominate completely over biological reproduction (according to the Life History Theory I detail in the paper).

Government programs to stop this will end in failure. The only way they could force people to reproduce is to control their lives with force - and that won't go down in a world with abundant energy (and a global brain). Governments will also worry about this less when radical life extension moves from theory to practical reality.