From the Urban Institute “People who experience high wage inequality during their working years are likely to experience high retirement income inequality, because Social Security benefits are tied to lifetime earnings, and people’s ability to save for retirement depends on how much they earn.”
I’m not sure how earning less than others got to be inequality unless your standard is everyone should earn the same income. Nevertheless, chances are if you are lower income while working, you will also be lower income in retirement which is why Social Security is designed to replace a greater percentage of pre-income for lower income retirees.
PS. peoples ability to save for retirement also depends on how much they spend