Agree 100%. The problem is really, GDP is in one currency. There should be a second metric, adjusted to local buying power, for countries with loads of internal resources, and production capability.
When I look at numbers, for example, which China spends on military spending, and research? Then try to equate it not in USD, but in local buying power?
And also consider many Chinese companies are state owned, including resources (mining), refining, and producing weapons...
Compared to almost everything the US GOV and the West do, being for profit...
It seems to me that China's military budget dwarfs all of NATO, in terms of buying power.
Yet most seem to not consider this. Even in planning.
US air superiority means little, if each US plane costs 40x a Chinese plane, and each US plane is swarmed by 100 planes at once...
(Just an example, viable or not)