“Once a woman is socialized to have an education and a career, she is socialized to have a smaller family. There’s no going back.”

Except that by the second half of the 21st century, few people are likely to have careers. AI will render ever growing portions of the population unemployable / “economically useless”. If you are just going to hang around at home all day, you might as well have a big family.

Even if birthrates keep declining, they might not keep up with the expected drop in death-rates. Biomedical gerontologists generally agree that biomedical molecular engineering will gradually extend maximum lifespan, and even enable rejuvenation. Our descendants may plausibly survive for millennia.

That said, I hope you are right. Seeing as we have spent the past half-century bursting through four of Earth’s nine planetary boundaries, cutting global fish stocks in half, shopping down a third of the Amazons, decimating insect populations by as much as three-quarter in places like Germany, eroded the quality of our soil, and ramping up specie extinction rates by a factor of 100–1 000 — A decline in our numbers would be a breath of fresh air.