The modern examples fundamentally misunderstand the premise, the empire didn't collapse, Syrians and Iraqis had less violent places to go, what if they hadn't? tbh no idea what the fuck happened in Somalia that warrants some investigation. I don't like referring to the Soviet Union or Yugoslavia as an empire but as examples of societal collapse and reorganization that does not support this essay's thesis at all...
WRT Rome, the Black Death, dynastic changes in China, well it's really easy to argue this point when you just shrug off massive mortalities and assume disappearing populations successfully resettled in the hills. For the egyptian example of commoners becoming 'richer', there are many examples of decreasing material sophistication in collapse periods. i find it hard to justify life being qualitatively 'better' for a commoner in sub-roman societies losing access to clean water, stone buildings with tiled roofs, roads, quality ceramics, utinsils, etc., and it's not like obligations of tax disappeared, they just might've paid less to smaller strongmen