I really think these numbers are antiquated, and with modern data science, a more robust picture of wages and employee compensation will emerge.

The median salary only accounts for the top 30% of Americans, and almost every job that pays more than $23/hr requires a college degree, not to mention that training / education / certification is financed through families and individuals, increasing their debt burden, which brings down their real wages. And that's one parameter, individual debt has also been increasing, as well as the gradual decline of the interest rates since the 70s.

All-in-all the bigger picture is more complex, and with every metric of inequality increasing, globally, I think the numbers calculated for inflation adjusted average wages for production and non-supervisory workers are antiquated.