One of the most basic needs when planning for a future is the prospect that the future will be better than the past. It's now very difficult to arrange that independently of constant advancement at work and constant advancement at work requires tremendous amounts of effort.
People are getting squeezed from both sides. I feel this myself, and I'm doing quite well statistically; white, male, educated, highly skilled and gainfully employed.
It has lots to do with it.
Brazil for example has PLENTY of space and cheap places to live (unless you want to live in São Paulo... like where I am now, the prices here ARE fucked up)
Yet marriages are going down to the point of scare the government too.
The reason for it is simple (there has been lots of research, not only here, but on other countries with declining births to dangerous levels): women prefer their careers to motherhood...
Even the UN gender economic report, state that it thinks is a good thing women have less kids because they can get richer (yes, that is written in the report, specifically, the report consider that countries where women have less than 3 kids, are countries that are awesome because they are reaching gender equality, since women with less kids can work more)
For men, it is the invention of no-fault divorce, that keeps marriage pointless (the point of marriage historically, in cultures where divorce was forbidden by law or by custom or by religion, was to force women stay in the marriage, and indeed in countries with no-fault divorce, no matter where, they keep finding that 70% of the divorces with no reason where started by women)
Let me be clear: I'm not suggesting that women have any societal obligations.
But given that we're all here today we can infer historically that women (as a whole) have liked having children at least some amount. Did they never ACTUALLY like it but that was their only choice? Or do they (again as a whole) enjoy motherhood but socioeconomic life is now so treacherous that motherhood is a luxury few can afford? Perhaps something else entirely from the false dichotomy I've suggested?
EDIT: I've accepted your premise at face value, but I'm not sure I should. I don't know how to properly caveat this comment.
It promotes the emancipation of women. When men care about children as much, there is no problem in having kids and a career for women (and men).
Once women have the freedom to choose not to get married, have kids, etc it seems likely that some choose not to and thus the rise of feminism is roughly correlated with a decline in birthrates.
I've tidied this up in a nice little causal package but it's quite likely not so clear cut. But it certainly does seem that way at a glance. Which is why the notion gets such good traction amongst some.
The UN report on gender equality in economy, writes explictly that countries where women have fertility of less than 3 is good, because research shows that women with high education has few kids, and thus it concludes that a country with not much kids mean that country has educated women, that from the point of the view of the report is a good thing.
If your "70% of no-fault divorces were started by women" statistic holds true, it could be because the greater economic power wielded by men made them pretty shitty husbands, and so when the opportunity arose, their wives divorced them.
I know plenty of western young people who have no interest in marriage, procreation or families. Maybe they're more interested in their work. Maybe they're more interested in rock-climbing. Maybe they're more interested in Pokemon.
More power to them, I say.