I tend to think people who argue about the economics or community issues tend to miss the forest for the trees. For the most part, other than biological drive, having kids is stupid. The systems that most people complain about failing - mostly around the community or economic costs of childcare - exist to make having children less stupid. We dramatically reduced teen and early 20s pregnancy rates, when hormones are yelling at us to make babies, and expected people to have them later in life when they're better at self-control?

Then, people who have a child that young are far, far more likely to have additional children. Outside of the first few years, a sibling often reduces the strain on the parents, and provides additional value. Your life starts to orient around the kid(s), and we get a couple of other hormone boosts so we love them and want more of them.

I am consistently confused that this conversation never seems to touch on just how many births are mostly because two people's biology overrode their judgement and that initial failure results in a feedback loop where you have another child or two. If that poor judgement doesn't happen, you don't kick off that loop, and then you're trying to rationally choose to do something that never made all that much sense in the first place.

I think it's clear that the reduction in teen pregnancy is indeed a big contributor to the decreasing fertility rate. I would guess the reason this doesn't get brought up in discussions about how to _increase_ the fertility rate is that reversing the trend on teen pregnancy is just really not a palatable solution to many people. Although there are some, usually on the religious right, who advocate for banning contraception, teaching abstinence-only sex education, etc., which would most likely have the effect of reversing the teen pregnancy trend.