To me, the lesson to be learned from the impending (hypothetical?) crises in China, Russia, India, and Japan, wrt their aging workforce and low birthrate, is diversity of the population. Having an ethnically diverse society enables migration of foreign ethnicities. Japan seems to be very highly racist, if you aren’t full Japanese. China is the same way, but with specific Chinese ancestry. There are ethnicities in China that have lived under Chinese rule for hundreds, if not thousands, of years and are still not accepted in their society. And India, well India has a caste designed specifically to keep the poor people poor, and the entitled ones elite. A system that puts the Jim Crow South and/or apartheid to shame, based on longevity alone.
None of those societies are likely to accept an influx of foreign immigrants (or even some locals) into their society as being equal to existing members. Yes, the USA also has a problem in that regard, but the USA is making great strides (at least, comparatively). Yes, conservatives fight the progress. That’s what conservatives do. They don’t want to change. Unfortunately, the world is changing, with or without them. It’s either change or get left behind. To be a global leader, you have to lead that change, not follow it.