Low birthrate isn't caused by high rent, but by a highly educated population and an economic system where kids aren't necessary to take care of you when you get old.

“and an economic system where kids aren't necessary to take care of you when you get old.”

Until you get terminal cancer and you are sent home to die. Then, I assure, a “kid” might be useful, because nobody else will give a flying fuck.

Says who? Meaningless statistics?

Talking to my circles of highly skilled couples most cite money as the primary reason they're putting off having children.

Most people I know who don't have children simply aren't interested in having children. And they can afford not to have children, so they don't.

Sounds like anecdotal evidence to me so I rather put my faith in the statistics.

I haven't seen any evidence that birthrates have anything to do with having a high income in developed economies. All the evidence I have seen points in the other direction, where when women's education and career are de-emphasized by the society, the birthrates are high.

If you live in the EU, downshift! With stable $30k you can easily buy a seaside villa in Bulgaria on a 7 year credit with today rates.

I've come to the conclusion that the economics are only part of the story.

Unless one is single, there's a ton of stuff you have to worry about, from finding a job for the spouse, to learning the language, subtle to not so subtle xenophobia, navigating a different social & political system, etc. Moving with kids makes things even more complicated, to the point that we essentially only have migration from poorer to richer countries. I'd wager immigration from the west to the east is almost zero. I know some cases, but it's a tiny minority.

Then there's the fact that most people don't want to live in another country, surrounded by foreigners speaking a language they will almost certainly never speak fluently themselves.