I don't think this shows that people who can afford housing have more kids. And it shows that even households earning over $700k/year are now below replacement (replacement fertility rate is about 2.1).

In the graph, fertility rates decline with income until around $275k. Those aren't families who can't afford housing. Those are well-off families with low birth rates. The birth rates start to climb in that chart only for the ~4% wealthiest families.

Also, you might reasonably conclude from that chart that rich women (in the $400k+ brackets) have more children, but that's not what the chart is actually showing. It's a synthetic total fertility rate, and not the actual TFR. They look at how many children women in that income bracket had this year, and estimate how many children they would have had if kept that reproductive rate for their whole reproductive period. That's going to misestimate the true rate due to selection effects. So, for example, a women who only wants one child is more likely to choose to have that child at 30, when her family income is higher, than at 18. But that doesn't imply she would have had more children if she had more money.

To put it another way, even if giving people more money had no effect whatsoever on their total fertility rate, you'd still expect the graph to curve up like that due to how people time their pregnancies.

If this chart showed what you seem to believe it shows, there would be glaring difference between brackets, similar to secular Jews vs Orthodox. What it probably shows is that pro-procreation minority partners has more leverage in pushing their wives/husbands towards having kids when they can appeal to already high economic/social status. Not making a significant change overall though.

Every economic bracket got smartphones and internet.

The men are playing Fortnite. The women are on TikTok and Instagram.

Babies went off trend so we could collectively do dopamine maxxing as a species.

Evolution didn't anticipate this.