No, tax revenue decline is only one facet of a declining population. A decline in population causes many other things that are dependent upon human beings to also decline: social interaction, art production, and a bunch of other stuff you might file under "economy": tax revenues, jobs, new businesses, new research, et c.

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.

> No, tax revenue decline is only one facet of a declining population. A decline in population causes many other things that are dependent upon human beings to also decline: social interaction, art production, and a bunch of other stuff you might file under "economy": tax revenues, jobs, new businesses, new research, etc.

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.