it can be, if you control with the Geni coefficient.

However large parts of many countries is rural, and different amounts for different countries, and that tends cause control issues.

But in general, a low Geni coefficient and a high GDP per capita means labour costs are high.

Yep. https://ourworldindata.org/grapher/median-daily-per-capita-e... for example. Although note the log-log axis which undersells the gaps between countries.