but their birth rates all collapsed within decades relative to the past, just as East Asia's did. They're just less far along in the process.According to your sources:
Iran's fertility rate is 2.09, which is extremely high by East Asian standards.
Saudi Arabia's fertility rate is 2.175, which is even higher than Iran's.
Finland's fertility rate is 1.42, which is very high by East Asian standards.
Ireland's fertility rate is 1.79, which is much higher than Finland and almost as high as Iran.
All of those countries have high birth rates compared to the secular, socially conservative East Asian countries. It would be considered a miracle by anyone hoping for higher East Asian fertility, if any East Asian country outside of North Korea or Mongolia had those fertility rates next year.
(That is assuming those numbers are right, which I have doubts as to, since for China, they claim the birth rate for 2022 is higher than in 2016 even though China had 45% fewer births in 2022 than 2016. The number of fertile women in China did not drop more than 45% between 2016 and 2022, so we know their data for China is not right.)
Secular social conservatism is a civilization-killer. This would be more clear if there were more religious socially liberal societies, but there are not because all the world's major religions are socially conservative. But there is evidence that secularism lowers birth rates, and when you add social conservatism and East Asian work culture on top of that, it's even worse.
The difference between 1.42 and 1.79 and lower or whatever, is just a few years in China's case. That's not much time in a demographic transition. All these countries will drop soon and noen of them have any solutions either.