We observe high fertility in those nations and cultures where patriarchy is legally and socially enforced, in particular Muslim Afghanistan and Christian Timor Leste. Affordability of family formation has little effect. Clearly males in patriarchal societies are highly motivated to have children. They will do whatever it takes so that they can afford a family.
Thus, if pro social behavior in a patriarchal society is rewarded by a wife and the ability to support a family, you get highly motivated workers and soldiers.
Some people have argued that this observation is psychologically unreasonable “The guys I know don’t want children”
Henry Dampier explains why males in our society don’t want children in his 2015 article “Why no one wants to be a patriarch”
If you want men to join the legions, you make it so that the clearest path to power for a typical man will be to join up with the legions, serve his time, and then marry and be fruitful on his plot of land. If you want men to form households, you given them rights over those households and the families that issue from them. …
… Men lost the right to use legal force against their wives and children in stages. …
… the disciplining doesn’t really go away from society. The switch is just passed on from the father to the policeman and the schoolmaster. The state’s hirelings retain the right to discipline children, although wives tend to be permitted to run wild, especially nowadays, restrained only by their desires and sense of self-interest.
The disciplining also changes from spanking to drugging, often heavy drugging of untested chemicals onto children. …
The reason why no one wants to be a patriarch today is that patriarchs have no more legal authority. They have no formal power over their wives or children. They only have influence. Influence is both fickle and distinct from power. When a child misbehaves in the modern world, there are only a few paths that a parent can take. They can verbally discipline the child (more likely to work in a higher-class household than a lower-class one), they can illegally or semi-legally beat them, they can take them to a psychiatric professional of some kind, or they can feed the kid to the justice system. Schools have their own corrections systems of varying levels of effectiveness.
Further, paternal heads of household can be deprived of their assets and children at any time at the arbitrary whim of their wives. The wife can commit adultery, and the man can still lose his property in the ensuing divorce. The children and the wife alike can be wildly disrespectful to the head of household, and the man has no recourse other than whining.
I was the boss of my family and I found being a patriarch and having children hugely rewarding. But then I am a grade A asshole, and I am not afraid to commit illegal acts, though I tend to consult lawyers on ways to weasel out or buy my way out if caught, before I commit them. It is hard to be a patriarch if you are a nice guy, or if you have respect for law and social pressure, because marriages on the Pauline model are illegal, being marital rape and psychological abuse. Marriage as it has been understood for thousands of years is illegal and criminal, so of course the population is collapsing. Workable families are similarly illegal. Indeed, these days any sexual interaction with women is illegal with the notable exception of hiring whores and escorts – whores, escorts, and porn stars being the only women who are likely to give you explicit verbal consent moment to moment.
Extrapolating my subjective experience, and the subjective experience depicted by Henry Dampier, fully explains observed fertility patterns, for example the very spectacular collapse of Japanese fertility.
People don’t want children as assets. Never have, never will. If you think we can modify fertility with the tax system read Luke 15:11-32 and 2 Samuel 15:2 – 19:6 to gain an understanding of human nature and the human condition.
The problem is that children can be taken away from a man and used as hostages against him. That is why men do not want children.
Marriage and family is outlawed, thus only outlaws have wives and families.