> The middle class have financially benefited very little from the past 20+ years of productivity gains.
More like the last 50 years.
https://www.pewresearch.org/short-reads/2018/08/07/for-most-...
"For most U.S. workers, real wages have barely budged in decades"
The TL;DR is that in 1964 the average hourly wage was $20.27. As of 2018, average hourly wage was $22.65.