Outside of either aggressive capitalist desire to continuously lower wages or some groups wanting to destroy Japanese culture, I've never understood why there was such an extreme panic by some about Japan's lower birth rates to the point that they urged mass immigration there. A stabilizing population on an island with limited space seems like a good thing. A little more space opens up for living and real-estate pric…
> A stabilizing population on an island with limited space seems like a good thing. A little more space opens up for living and real-estate prices might become more favorable. Maybe there's room for more parks and other things that make life good. When conditions become more favorable, people will be able to reproduce more.
Population density is not homogenous. Excluding pandemic era, the trend has been decreasing population density in the countryside and smaller cities, while more population moves to the big cities. In general, population size need not correlate for the average persons lived population density.
> I'd say that the human desire for reproduction might work in the same way, only instead of prey, maybe real-estate prices and quality of life is the cyclical variable to note.
This is likely true on the extremes to some degree, but I haven’t seen much evidence that this is a driving force of population dynamics.
> I've never understood why there was such an extreme panic by some about Japan's lower birth rates to the point that they urged mass immigration there.
This is generally because the population is not stabilizing, it’s on the verge of collapsing. If fertility rate rises “naturally” in the future, as you suggest, then it’s obviously not an issue. But maintaining a 1.3 or lower fertility rate indefinitely will result in an exponential decay of population which could itself result in a decline of living standards. For example, if the population decreases too much to support a high speed rail system so these are abandoned as unprofitable.