So many people treat parenthood as a checkmark on the mandatory itinerary of life and once they check it off they just "eat the cost" and pay to have the kids taken care of.

Both those parents, and the poor parents who cannot afford the state / capitalist solutions to child rearing, are being negligent. Kids need familial bonds and constant social contact with their kin group to thrive. You don't drop them at random daycares every day for eight hours starting at six months and produce healthy progeny.

Raising kids is at least a part time job for both parents. Not in monetary expenses, in time. Putting in less than that at any point before pubescence can be catastrophic to the growth of the child. But as a society, because that cost is for most people untenable, they still want to "fulfill their obligation" to past generations, and have kids they cannot adequately allocate time for and end up producing descendants who suffer throughout life for it.

It is an absolute real conversation that needs to be had, that the true cost of parenthood is astronomical in todays society, and that almost nobody is in a financial position to fulfill that obligation such that they aren't risking harm to the child. We haven't had an adequate availability of time on the part of both parents to raise their children since 80% of the population were agrarian farmers* and we have seen rampant expanse of mental illness and maladjustment to society for it ever since.

* of course said farmers were very rarely good parents. Using your kids as hard labor from a young age, using violence as a coercion tactic against them, treating them like property and an investment rather than people, not feeding their curiosity or inquisitiveness out of your own ignorance and simple mindedness taught by your parents. It was a real mess that compulsory public education in part did a lot to stop, but that doesn't preclude the availability of parents and family being so critical to the well-being of young minds while also being absent from contemporary society for the vast majority of children.