First, its not my theory. Its stated in a UN report.
Also, Japanese women are feminist enough, education, wanting career, no wanting families, etc. I could go on.
You are going against the UN themselves here.
Your position that is this current downtrend will change cause reasons. The current situation heavily favors women, they enjoy it. Media and education heavily enforces not to have kids and to work, etc. Some people here mention about conservatives having kids, but they could go to college or university or get influenced by pop culture and boom no kids.
Could what you say happen of feminism facing a backlash? Possible but highly unlikely cause as what a lefty male advocate group states, there is a women are wonderful effect and we can't have the women be unhappy now can we?
Not 'cause reasons.' To put it simply, when you hit the point of economic collapse due to demographic collapse, the social forces that result in declining birth rates start to substantially change in a large number of ways, and that by itself will force things to change.
And I don't mean 'economic decline.' A first-world society can take a 20% economic decline over 5 years without being
forced into major cultural change. I'm talking about 'your ability to maintain modern supply chains breaks down,' and you have a year where economic output drops by
half, or possibly as much as 90%. When you get that kind of mass-impoverishment, suddenly sex is one of the cheapest and most available forms of entertainment, and a lot of people are unemployed. Even if birth control is used at the same level it was before, it's not perfect, and the massive increase in sex will result in higher birth rates.
Economic collapse is just one factor that can force this kind of change. A few others:
1. Preference cascade. A number of studies (quietly buried for being politically incorrect) over the years have shown that 'housewives' tend to be happier than 'career women with no family,' and strong propaganda can only suppress that fact for so long. There's already large numbers of professional women who, when they hit their mid-30's, ask themselves 'Is this really making me happy?' Then find a man who meets their (often steadily eroding) standards as quickly as they can, get married, quit their job, and pop out a kid or two before it's too late. This isn't enough to save the birth rate, but it's a symptom of the same thing that can cause a revers cultural swing.
2. Cultural transformation. Just as secularism and post-modernism have swept western culture over the 20th century, Christianity could experience a major resurgence as a cultural force in the 21st. In Europe, Islam might become predominant. It's not something that has sometimes been addressed here, the fact that in the US at least, stable marriage rates and birth rates are much higher amongst more seriously dedicated Christians. Regardless of whether it's Christianity, Islam, or something else, the current cultural zeitgeist is entirely capable of changing.
3. Major world conflicts and economic transformations. Collapse of the globalist economic system would have tons of follow-on consequences. The sort of economic and cultural pressures this can bring to bear on most nations, changes what occupations have higher social status. If your people experience a famine, or even just a half-famine of preferred foodstuffs, suddenly a significant portion of the population will have a lot more respect for farmers, fishermen, etc. If a war hits where your nation is existentially threatened, soldiers suddenly become a lot
sexier, and a lot more women will be interested in that kind of mate, etc.
4. Finally, the reason it
must change. If your population decreases to the point where you've devolved into a subsistence population in a post-apocalyptic ruin of your own civilization, birth control won't be available, and most women will happily attach themselves to a man who will fight to protect them. This last element is why the current cultural trend literally
cannot last forever.
There's all kinds of reasons why the cultural hegemony of 'women should economically function exactly like men,' or more egregious forms of feminism can break.
