The data tell a different story. I've offered them in a another comment, but see increasing household income for every quintile here [1] and decreasing poverty here [2]. While income inequality is increasing, that doesn't mean quality of life is decreasing or "moving backwards." [1]
https://www.advisorperspectives.com/dshort/updates/2019/11/2...
[2]
https://www3.nd.edu/~jsulliv4/2017%20Consumption%20Poverty%2...