If you had read the article, you would have learned that Devereaux contends that the "change and continuity" is promulgated primarily by historians studying the Medieval period, and not those studying Classical Antiquity.
The author shouldn't have made such a pat assignation of blame. But, erm, I was supposed to subsume his (in my view flawed) sorting argument into my thinking, and not having done so shows I didn't read the piece? How odd.