The article never mentions the Muslims. It was the Muslim invasions that destroyed much of “classic” civilization, which was making a comeback in the 6th century.
Muslims destroy the productive areas in North Africa, the Middle East, and into Asia.
See Mohammed and Charlemagne Revisited
https://www.amazon.com/Mohammed-Charlemagne-Revisited-History-Controversy/dp/0578094185
European lost most literacy because they lost access to cheap writing material, papyrus. They had to use parchment, about 100X as expensive.
“The article never mentions the Muslims.”
Yeah, I noticed that and you beat me to the post noting such. Kind of erodes the credibility of the author and article...