Japan is an economic outlier in a lot of ways (i.e. savings and birth/immigration rates).

And I think it's a great example that most of the actual drivers of economic outcomes are unmeasurable. What we actually measure and react to are themselves second order effects of those primary drivers.

Which is why we can compare two situations with similar (second order) metrics (but different primary drivers) and be puzzled by different macro outcomes.

I think instead is that the mistake was to measure them in terms of money, which is a token, a signal, and hence not "real" (not to mention subject to feedback loops when trying to focus economic policy on that signal !)

As you suggest, it's important to make a clear distinction between nominal and real variables in economics.

However, nominal variables are also subject to feedback loops.

That's because they haven't printed enough money.

If they printed enough money, they could generate all the inflation they wanted (or live in economic utopia.)

Basically, keep using newly printed money to buy up assets around the world. At some point you either own the globe, or you'll get the inflation you wanted.