It ain't necessarily gold, but a dollar 'IOU' in the end should give the holder something to concretely purchase besides military equipment.
You can argue dollars can also buy 'IP', but IP is virtual and only as good as the police and military enforcement of its regulation.
You can argue dollars buy oil, but once again only because of military enforcement of the imposed rules of not to trade in other currency.
In the end an empire based on massive consumption of the world's resources in return for not much else besides the threat of 'take this paper or we bomb you' will not hold.
As for the brain-drain. This was/is still a huge thing. But it hinges on the desirability of attracting the right brains. If you abandon meritocracy as the US has been speed-running, why would a capable person want to go/stay there? Seems like the attraction incentives are there more for the subpar performer in the 'modern' US.
You can argue dollars can also buy 'IP', but IP is virtual and only as good as the police and military enforcement of its regulation.
You can argue dollars buy oil, but once again only because of military enforcement of the imposed rules of not to trade in other currency.
In the end an empire based on massive consumption of the world's resources in return for not much else besides the threat of 'take this paper or we bomb you' will not hold.
As for the brain-drain. This was/is still a huge thing. But it hinges on the desirability of attracting the right brains. If you abandon meritocracy as the US has been speed-running, why would a capable person want to go/stay there? Seems like the attraction incentives are there more for the subpar performer in the 'modern' US.