I won't deny your points but two additional things happened during the period where wages diverged from productivity, maybe even three more.

First, greater international trade. We moved a lot of good paying jobs overseas. I the town where I grew up the textile mills and shoe factory closed, and the jobs were moved overseas.

Second is automation and computerization. That increased productivity and also simplified the work so less skill was required of the workers, so they were paid less.

Third maybe, got to think about this one more but the switch to more of a service economy, productivity is harder to measure, and wages were lower.

TEK