This is simply not true. Not even close.
I recommend watching:
https://www.gapminder.org/videos/will-saving-poor-children-l...
or, if you can spend more time,
https://www.gapminder.org/videos/dont-panic-the-facts-about-...
or any of Hans Rosling's TED talks. And you'll find that your statement I quoted above is simply wrong.
Play the following graph from 1800 to today:
https://www.gapminder.org/tools/#$state$marker$axis_x$which=...
It's very clear where we're headed and we're actually closer to the stable point, given China and India are already near the birthrate of 2.
> ... are still happily multiplying in an unsustainable way.
See the graph above. This is already not true.
> Unless we manage to export this kind of progress
This has already happened mostly. Africa is the laggard currently but is already rapidly catching up, and it's crystal clear that we'll get there.
I recommend taking the gapminder.org test. I think you'll be surprised how wrong you are.
What society has ever done that?
From the article: "At the festival, Romulus gave a signal, at which the Romans grabbed the Sabine women and fought off the Sabine men. The indignant abductees were soon implored by Romulus to accept Roman husbands".
That the second phase may have employed carrots as well as sticks does not detract from the fact that the Romans have thereby managed to expand their reproductive capacities while simultaneously contracting that of the rival Sabines.
I fear that was a misunderstanding, good sir. I didn't mean that women were ever press ganged into the army, but into producing the next generation of recruits. Frankly, I actually lold when I got that just now! =)
Thus the constraint may just be "time to make babies".
Most parents want to provide a standard of living to their kids that is better than what they grew up in, which costs significantly more to provide.
Kids didn't always have their own bedrooms or cellphones, and in an agrarian society kids were useful as extra "free" labor. The shift to cities has rewritten the economic calculations potential parents do.
Affluence means you have the means to take care of yourself, so therefore don't need to spend the effort of raising kids for this reason.
But birth rates have been declining in first-world countries for a long time in the absence of this kind of constraint, and the Foreign Affairs article specifically notes that both Malthus and Paul Ehrlich's "Population Bomb" doomsday resource-shortage scenarios didn't come to pass.
The Earth certainly does have some kind of carrying capacity for humans, but that's not the limit that's being it, it's something else.