> I was quite surprised when recently I realized that the median (adjusted for PPP) disposable income in America was the highest in the OECD
That doesn't really tell you all that much useful. Disposable income just deducts taxes from your gross income. What really matters is the cost of those other things we're talking about: food, housing, healthcare, childcare, etc. When you subtract those out as well, you get discretionary income, and I bet the US is not leading at all there.
It’s not really a straightforward comparison because those categories are discretionary to an extent. For example people in the US seem to eat out at restaurants far more than in other countries. That would certainly increase food spending but clearly it’s a choice people make to improve their life and doesn’t represent a defect in the economy.