[slantedview]

Per-capita GDP is a good measure of how much wealth a country is producing, but it says nothing about how that wealth is distributed. While Japan's per capita GDP is lower, it's a vastly more equal society than the US, where a large portion of that wealth is captured by a small % of people. The unsustainability of this, long term, is part of the overall debt story.

[Manuel_D]

Distribution of wealth has a lot to do with inequality and related social unrest, but not really that relevant to financial sustainability. If anything, the fact that so much wealth is concentrated at the top means the US could reduce the debt a lot by only taxing the richest 20-10% of the population, and not raising taxes at all on the rest of the populace.