The income inequality in the US is not that visible in day-to-day life. A large fraction of the income inequality is a side effect of the scale of US geography. The States with the highest and lowest median incomes are separated by 2x income and 1500 kilometers. It is also worth pointing out that even the poorest US State (Mississippi) still has a median income that is the same as Germany, so "poor" is relative.

Different States have different economies due to geographic locale, history, and specialization. Consequently, the US has States that specialize in agriculture, manufacturing, services, technology, natural resources, etc which have very different economics and compensation structures which is reflected in local incomes.

The median income is much higher in Washington than Mississippi, for example, but that doesn't imply anything about the distribution of income within those States. It would be like comparing incomes between the Netherlands and Romania.