Nicely done. I was charmed by the perspective in this article, which struck me as at that of a systems archaeologist rather than someone who was there at the time using the interfaces. I cut my teeth on twm and CDE, eventually moved to fvwm, and then turned pro by becoming a SGI IRIX admin.
The diversity of window managers at the time was impressive; I'd liken it to cars in the 1950s and 60s with chrome, vents and fins in every possible configuration in stark contrast to today's bland automobile designs. The Enlightenment WM (https://en.wikipedia.org/wiki/Enlightenment_(window_manager) ) was a particular favorite due to its customization possibilities.