they seem to be frozen in time

Much worse than frozen. The birth rate is plummeting while the population ages out. Their job participation rate has been sliding as a result. More and more of the economy is tied up in managing the depreciating real estate and financial assets, while catering to the wealthy retirees in their later years.

I'd say they're ossifying and crumbling. I'm curious to know what their breaking point is. At what point does the Japanese economy become unsustainable, what with tightly closed borders and a shrinking population?