> GDP/capita is often a relatively useless metric in modern times.

"Often" is the wrong modifier. GDP/capita aligns very closely with material standard of living for the median person. If you look at the GDP/capita growth in India and China since 1990, or South Korea, Singapore, and Taiwan, since 1950, that reflects very real increases in material standards for ordinary people.

There's two, relatively well-understood situations where GDP/capita isn't reflective:

1) Countries where the economy is dominated by resource extraction or tourism 2) Tax havens

But it's pretty easy to tell whether one of these exceptions applies. It doesn't in the case of Poland, which has a broad, diversified economy with a high level of industrial production.