> PPP matters on an individual level, but not at all on a national level. GDP at market exchange rates is what actually matters in terms of what a country can accomplish on the world stage.
That's demonstrably false cause the global super-powers (i.e. the US, Russia and China, maybe India, too) mostly depend on their internal markets only when it comes to their war industry and to paying their soldiers. When it comes to that PPP is a lot closer to the truth on the ground.
If we're talking military only, then you have to look at defense budgets, not GDP. The US defense budget is still much bigger than China's and Russia's combined, even after controlling for PPP.
By "what a country can accomplish on the world stage", I meant a more holistic view of what a country can do, such as investing, R&D, exploration, etc. (and also military).
That's demonstrably false cause the global super-powers (i.e. the US, Russia and China, maybe India, too) mostly depend on their internal markets only when it comes to their war industry and to paying their soldiers. When it comes to that PPP is a lot closer to the truth on the ground.