Japan is hardly the first country that comes to mind as "functional". They've been stagnant for several decades.
From that nonsense, it becomes even more foolish to assert that Japan (a G8 nation and the 3rd largest economy in the world) is not "functional" by focusing exclusively on it's economy.
You can describe it as a form of a Ponzi scheme, the idea is that we must increase populations so we can continue living on the current living standard, not a future increased living standard.
What would it take to get to an improved living standard according to the this ideology? Doubling of populations? Tripling?
Not necessarily. The drive to keep a positive population growth rate is the need to provide resources to maintain the older segment of the population without draining the resources of the economically active population, aka work force.
In a more and more high skilled society, increasing population can have the opposite effect, do everyone have the skills and knowledge to operate in high skill society? If not, who will feed them?
Combine this with automation and old truths about increasing population to maintain standard of living falls apart.
On top of that, what the lockdowns has showed us is that many jobs are not actually needed for having a functioning society.
Taking a purely economic view of these things is to misunderstand what is happening. Sure, it's an economic stagnation/downturn when new jobs aren't created, but more important than the money is the loss of the things those jobs produced in society outside of their economic impact: tools, art, research, creativity.
Japan's current population growth rate is around -0.2%.
It's safe to say that the "evaporating population" hypothesis and it's hypothetical cataclysm on the arts doesn't make much sense nor has any bearing on reality.
> Taking a purely economic view of these things is to misunderstand what is happening. Sure, it's an economic stagnation/downturn when new jobs aren't created, but more important than the money is the loss of the things those jobs produced in society outside of their economic impact: tools, art, research, creativity.
Your "purely economic view" strawman doesn't pass muster. For starters, GDP reflects transactions and economic activity, and money is just the unit of account used to perform those transactions.
Another one-party democracy that worked well, at least for a few decades, is Singapore.