This seems to me only partially true. Sure if everyone had one-percenter level resources they'd be more inclined to procreate, though the cultural change and the shifted focus to individualism and one's own experience in life (YOLO thinking, if I may) probably has as much or even more effect on it.

As an anecdata, most people I know are somewhere on the low-class to upper-mid class, and the ones who want kids seem to always have at least one, consequences be damned, and the ones who don't, often don't put a price tag on it and merely use it as an excuse if they feel pressured.

Also the `natural instinct` may not be a given here, since up until recently the instinct to have sex and procreate meant the same results for humans just like other animals, which no longer holds true either.