I do not think that is correct? This actually shows stagnation for at least 2 decades in real median household income:
https://en.wikipedia.org/wiki/Household_income_in_the_United...
Source: https://en.wikipedia.org/wiki/Household_income_in_the_United...
First, note that this is median, not mean, so it’s not skewed by outliers. Secondly, t’s real income, which means it’s already inflation adjusted. Finally, it’s a measure of households not people. This understates the per-capita gains, since the average household size has shrunk since the 80s. Arguably, increasing prosperity is part of why people now choose to live with fewer people such as extended relatives and housemates.