Japan's median household PPP income is lower than the UK's, which is already too low.

The depreciating houses thing he complains about is actually great policy, unlike the UK - recently I saw one of those "weird Japan" articles about how someone built an accurate English house in Japan, but UK planning is so strict it probably cost less than doing one in England.

But for other reasons they're not that rich, not that productive, and it's not getting better.