This really took off in the Reagan years where real wages stagnated [1]. It was from the 1980s where you started to hear statements like "wage incresaes should be tied to productivity increases" [2]. If you parse that statement, it means no cost-of-living increases ie a decrease in real wages.
All of this is wealth transfer to the very rich and entirely intentional.
[1]: https://www.epi.org/publication/charting-wage-stagnation/