Is it even a crisis for capitalism? Modern day capitalism seeks to eliminate workers, the ideal for the capitalist is to make a factory full of robots with like 10 employees that manage and service them. As factory work dies the population stabilizes (it doesn't shrink, it just stops going up year over year) and the remaining population performs service jobs that can't be performed by AI/Robots or a select bit of high paying factory jobs where robots cannot yet perform the factory task.

In an even more dystopian outlook the capitalists don't even want people for service, they likely would want robot and AI service (waiters, barbers, etc) in the long game to eliminate the need for serfs.

At the end of the day the cry about population collapse and declining birthrates only makes sense when you add a desired ethnicity before the term. Example [White] birth rates or [White] population collapse. Elon Musk isn't worried about the birth rate of Japanese or South Koreans. This whole thing is about racist views on world ethnicity.

And a medium term crisis for elderly care

This is deeply myopic. The problem is not low birth rates, but uneven demographics.

How does, let's say, marxism leninism deal with the problem of uneven demographic distribution? I've never heard of any even theoretical fixes from them for that.

https://www.macrotrends.net/global-metrics/countries/CHN/china/birth-rate -- do you think China doesn't view this as a problem?

With the introduction of automation every decade (currently AI is the big one), unemployment rates will go up so we don't even need as many working. Our capitalist brains just can't fathom "handing out" extra resources.

Hence the agenda of the current American regime. Outlaw birth control. Eliminate public education. Health care will be too expensive for most workers. And over it all, evangelical Christianity keeps a poorly educated workforce in line. So you end up with a working class who breed fast, die young, and have no concept that life could be any other way.

Sounds catchy, but I'm not sure this is really true. Capitalism is about owning things, not selling things.

It's a problem that there will be fewer people in the generation below ours to support our generation in our dotage. This problem is the same regardless of your economic model. Fewer people in the working pool and more people sick and elderly is a bad time.