Tragedy of the commons, but the humans are the cattle.
For each employer, it's most profitable to work your slaves to the bone, even if it's better for every employer to collectively treat their employees well
The only difference as compared with the old, outspoken slavery is this, that the worker of today seems to be free because he is not sold once for all, but piecemeal by the day, the week, the year, and because no one owner sells him to another, but he is forced to sell himself in this way instead, being the slave of no particular person, but of the whole property-holding class.
Friedrich Engels, The Condition of the Working Class in England (1845)
I agree with the sentiment here, but doesn't birthrate decline correlate with increased income? National birthrates always fall as a country's per capita income rises.
Well, they say that, but if you poll Americans of birthing age, most say they want more kids but can't afford it. Also, on paper I make more than my dad did, even including inflation, but I couldn't get within a MILE of providing two kids with the lifestyle he did on what I make, so... IS income really increasing in these places?
Hot take: birthrate is high when it's economically profitable to have kids - helping hands all around to take care of stuff. When they're a financial burden for the rest of your life besides substantially worsening your quality of life, birthrate plummets.