> Those last few generations have no technology, they're huddled around in the dark trying not to starve.

At that point, the birth rate would quickly rise again, no?

Because if you're back to living in a pre-industrial society, kids suddenly have value again.

So it's likely that either there's a point of equilibrium or the population keeps swinging up and down. Total extinction seems unlikely.

Indeed. And in context of India since that's what Economist's article is about. Having higher population growth is just insanity to me. After destroying land, water, air, forests, mountains and still barely enough for hundreds of millions souls I am not sure how population deflation can be a important concern at this point.