The major remaining factor favoring the US is our extremely advanced military. "If you don't want our dollars anymore, maybe we should just invade, capture your natural resources, and make you pay us taxes!"
Ultra low cost US equity ETFs such as SPY are not really diversified. Other major asset classes (commodities, real estate, foreign bonds, etc) are necessary to be truly diversified and if you want to hold these as a 'mere mortal' you are going to have to accept 0.75%+ fees
5 Reasons to Save the Greenback [View article]
If only our next president could be so brazen.
Disclosure: Half joking
David Swensen On Keeping It Simple [View article]