Wouldn't you expect that to be a one-off change that exhausted itself within a decade? And then a return to old income growth rates? Like, middle class income

Wouldn't you expect that to be a one-off change that exhausted itself within a decade? And then a return to old income growth rates? Like, middle class income growth has been stagnant for several decades now despite steadily increasing productivity, how can you explain that whole period using demographic shifts around 1972?