Beneath the surface, AI replacement works in such nations because most of them are below replacement rate and continuing the downward trend. The reality is more likely that people already don't, or aren't going to, exist to fill those jobs anyway, so they don't need to create said jobs if AI can perform the role. It is sort of "freeing up the workforce" in a sense, but moreso it's eliminating the cost of management and resources for handling potential workload that would require more bodies. (Yes, the Japanese are overworked, but their economy has been in a sorry state for a long time already, overworking might be a consequence of that, i.e. the weak currency and higher costs)

It doesn't work in a nation that's trying to grow, maintain the current economy, or of course, replacing its native population with more unskilled. Although, if it's replacing white collar work outside of code monkeys to maintain the AIs, then it leaves blue collar work mostly intact. The question remains is how fast does the change come and does it come so fast that it implodes an economy (maybe a civilization) due to mass unemployment, which I think could happen regardless if there's large amounts of low skilled workers bumming around