It sounds like we need a new metric. Something like "military purchasing power parity" (MPPP). A conversion factor C would be determined for each country based on how expensive it is to locally produce tanks, aircraft, etc., train and maintain troops, etc. Then their nominal GDP would be multiplied by C to get MPPP GDP.
For example, just looking at troops, if it costs $100,000 per year in overhead-included costs to maintain one US soldier but only $10,000 to maintain a Chinese soldier, then that would help their MPPP. Large defense contractors with cost-plus contracts would influence the US's MPPP, but so would corruption in China.
An even better metric might be WMPPP (wartime military purchasing power parity), which is probably the real metric that counts and determines which country is a superpower. This is what the MPPP would be in wartime. For example, the US spends a lot on troops and equipment in peacetime, but in wartime it could operate much more efficiently. See World War II.
Another interesting metric would be how quickly a country could ramp up its military production within 1-2 years assuming a major war broke out, because a war against another superpower probably wouldn't last very long.
For example, just looking at troops, if it costs $100,000 per year in overhead-included costs to maintain one US soldier but only $10,000 to maintain a Chinese soldier, then that would help their MPPP. Large defense contractors with cost-plus contracts would influence the US's MPPP, but so would corruption in China.
An even better metric might be WMPPP (wartime military purchasing power parity), which is probably the real metric that counts and determines which country is a superpower. This is what the MPPP would be in wartime. For example, the US spends a lot on troops and equipment in peacetime, but in wartime it could operate much more efficiently. See World War II.
Another interesting metric would be how quickly a country could ramp up its military production within 1-2 years assuming a major war broke out, because a war against another superpower probably wouldn't last very long.