In my uneducated opinion, theres lots of factors. However, economy/wealth is by and far the largest one, because almost everything else seems to have a price tag.
And even if they weren't more out less directly equitable, how long would it take for one to pull up the other.
China has 4x the population the US does. The US won the cold war because it had a larger economy, partly because it had a larger population. That's not how any future conflict is going to shake out
In my uneducated opinion, theres lots of factors. However, economy/wealth is by and far the largest one, because almost everything else seems to have a price tag.