Japan continues to have an HDI comparable to similarly sized France [0] despite having almost double it's GDP and a median age comparable to both Germany and Italy, and a TFR comparable to other European states [1].

It is also able to field a navy and armed forces that is independently able to hold off against China. Meanwhile, look at Europe and how it's managed the Ukraine Crisis.

[0] - https://hdr.undp.org/data-center/country-insights#/ranks

[1] - https://data.worldbank.org/indicator/SP.DYN.TFRT.IN?most_rec...