As an American, I considered popping out a second kid (one more than I’d originally planned) just to take advantage of the benefits my home country doesn’t offer.
Free prenatal care- it falls outside of national health care since it’s not an illness so the set you up with a coupon book for visits.
Low cost hospital stay for birth plus the option for a week or two of care after the birth.
A check with a lump sum payment that covers most or all of the cost of birth.
Monthly child Affordable childcare/preschool/after school care
Paid sick leave/annual leave
Extra dental and health insurance for kids on top of the national healthcare
Regular health check ups run by the city
And my favorite - a place to set your baby while out doing things whether a crib at city hall, a play space at the post office, and baby chairs in the bathroom stalls.
I can’t speak for all employers, but the Japanese teachers I worked with made good use of their three year maternity leave. It was Kyushu though, they do big families down south.
If I had to say why the birth rate was so low I’d say it was the men. They by and large absolutely refuse to get with the times. So women are choosing just not to get married altogether. Not less kids, just throwing the whole system in the dumpster and refusing to participate.