Then that might be the destiny of the human race, since all trends point to decreasing fertility as countries industrialize. I guess in a way it is natural selection, since the individual humans become more productive you naturally need less people. Maybe in an ironic twist, countries that fail to industrialize will live on?East Asia is is a better position than most of Europe as their fertility rate drop occurred much later. The reason the drop is lower is because of the lack of immigration. If you look at the native populations of most European countries much lower than the national rate.
The concerning thing is I've not seen a single country implement anything that could be considered potentially successful. It's all things that were implemented and failed before.
The way I'm increasingly seeing it is natural selection. If a society needs to implement draconian measures to keep its people reproducing it doesn't deserve to exist. I wonder how many tribes in prehistorical times went extinct because they didn't bother learning to cultivate fire, save up enough food for winter, etc.
Morbid jokes aside. China implemented pretty draconian measures (1 child policy) to control the exploding population. There's a lot of positive arguments that the policy helped propel China to where it is today. Now China needs to reverse the trend in the other way, I don't see why "draconian" policies shouldn't be implemented in some form, if the 1 child policy was introduced before and people's preference back then was to have big families. There are ways to heavily incentivize and change people's thinking. It's like tending the garden, if left naturally there'll be weeds all over the place. With some intervention, the plants will grow up well.