The study that graph is from literally says that millenial growth has stalled compared to baby boomer and silent generations:

https://www.federalreserve.gov/econres/feds/files/2024007pap.pdf

We confirm that there has been a slowdown in intergenerational progress, except for Millennials who saw their incomes grow slightly faster than Generation X but still more slowly than Baby Boomers and the Silent Generation. Intergenerational progress has remained positive for all generations.

First, we find that the higher household incomes of Millennials relative to Generation X, through their 20s, is a result of dependence on their parents rather than a rise in their own market incomes.