[tirant]

If that’s indeed the case, how do you explain the lack of catastrophe in Japans economy ?

Japans big catastrophe happened in 1990 with the bubble bursting, but that was years before the peak in working age population. Since then, the economy has not improved much but also has remained somehow stable.

[Larrikin]

All the jobs in Japan are hard work and low wage. If you're relatively poor and moving from south east Asia, it may make sense to immigrate to Japan. If you're a developer you typically will make half or less than half the salary, for longer hours on some old stack.

When discussing where to live my wife realized that she would potentially triple her salary as a nurse with 10+ years of experience.

Tourists like Japan because it is clean, safe and relatively cheap, but given the option it really does not make sense to work there.