I'm not so sure. I think it's a mistake to look at this on a country-wide basis:

- The cost-of-living in India in Bangalore or Mumbai -- at a standard to afford a family -- is astronomical for relatively educated individuals making $10k/year. That's where affluent people live. It's not until you get into the real elites making $100k/year that it's easy again. That's the same worldwide. Even very poor countries have areas where these dynamics kick in.

- Where many poor people live, for example, on rural farms, it's possible to have lots of kids.

"Generous maternal benefits" don't come anywhere close to filling this gap.