I haven't had the chance to watch the documentary yet, so I can't yet comment on the content of the video, but internet discussions of the current looming Japanese demographic crisis focus on the hikikomori/otaku cultures, as a ubiquitous thing in the country. I don't dispute that as a major social problem, but I think all too frequently we fail to focus as much on social expectations when it comes to women.
There is a reason why 70 percent of women drop out of the work force after having their first child (
Global Issues). It's a continual belief within the work culture and within management that women simply can't accommodate a working life on top of raising a child, hence why there is still a dishearteningly vast preference for men and a wide breadth of career-building opportunities for men. I don't doubt that there has been significant improvement, but there is still a majority mindset (51%) sticking to the belief that women should stay at home, while husbands serve as the breadwinners. On top of that, bosses preferring to exchange a female worker for a male rather than allowing her paid leave. And women who have successfully made something of themselves in the career ladder just don't have the desire to risk and lose all that to raise a family - or even be in a relationship - fearing that they may not be able to even come back.
And sadly, that seems to be the social dichotomy for women in Japan. A personal life with a partner who may want to start a family, or to find that career window wherever possible and to make the most of it. And given some efforts made to allow more Japanese women to succeed in the workplace, while their numbers may go up, the pervasive socially conservative mode of thinking is going to remain. On top of that, Japan remains hostile, at least not open to, immigration, so unless social thinking quickly and drastically changes, the population decline will continue, and the economy will continue to stagnate for even more decades to come as a decreasing working-age demographic has to keep the country economically afloat while supporting pension schemes for the vast elderly demographic.
/frankly, I'm not expecting much success from Prime Minister Shinzo Abe either.