It seems to me that many people who have kids early (and often have many kids) are those who got them, even if not by an accident, then at least without thinking much about it. Those who try to learn as much as possible first, often decide that it overwhelms them. Planning ahead also seems to be correlated with better use of birth control.

I agree that there is some evolutionary negative feedback loop but we are doing are best to work against it because that seems like a right thing to do.

The feedback loop we haven't handled yet is automation which is increasing minimum IQ required to get a job.