Inflation from 15 years ago to now is 33%[0]. Inflation from 30 years to now is 107%[0]. So yeah, median incomes are dropping.
[0]: According to this calculator - https://www.usinflationcalculator.com/
[0]: According to this calculator - https://www.usinflationcalculator.com/
Here's the equivalent chart without inflation adjustment, which gives the (incorrect) impression of sharply rising incomes: https://fred.stlouisfed.org/series/MEHOINUSA646N