In the old days countries used to measure their wealth by ‘productivity’, which was how many labours-hours were required to convert raw materials into a finished good.
This is a relative measure of wealth, since if productivity goes up an economy is wealthier than before.
But its very hard to measure absolute wealth, and it certainly isn’t any GDP or GNP, cumulated over many years, because these are measured in currency units.
And currency units only show the relative wealth between nations (based on the total number of notes in circulation and their exchange rate).
I think a better measure of wealth is some complex function dependent upon the % of an average person’s time required to just sustain themselves.
Before the industrial revolution this was almost 100%, with only a handful of people having spare time. Say 99.9%.
Today in the West it must be much less than 1%. The other 99%+ of the time can be spent sleeping, but usually it is also spent consuming unnecessarily.
So tracking this thought through, wealth might also be measured by (consumption (in say energy units) not related to subsistence) x (number of people).
(Note here. The odd thing is the discrepancy between the place of consumption and production. China makes stuff and then lends the proceeds to the U.S so the U.S. can consume it. Odd and it can’t last).
The energy units should only be based on the non-renewable resources consumed (say oil, superphosphate, species, etc).
So what I am really saying is that ‘wealth’ is a measure of the consumption of the planet’s finite and non-renewable resources.
Enjoy it while it lasts!