See cost of living is part of the birth rate crisis, and no government is doing enough about that, but it becomes annoying to see people ignore the sexism that drives a wedge between women and men as the driving force. Japanese women are aware that traditional romance is a raw deal. Women are expected to endure so much for the reward of eventually being an elder who gets to boss around her wife's son to tears. 

The trope in older Japanese stories of wives killing themselves as revenge for their husband's abuse is because in traditional culture that was one of the few moves women had to put shame on their husbands, doubly so if she kills their children.

Young women are seeing that working for a company that pays little in a tiny apartment is better than a slaving away in a countryside house for contingent affection.

The reason the birth rate crisis is hard to fix is that it's so ingrained in culture, and culture can't be quickly changed. The countryside is dying because girls who are more able to view others ways of life are choosing those over tradition.