My suspicion about why this is the case is rooted in the responsibilities engineering shares with product and design at the management level. In an environment where very little unilateral decision making can be made by an EM, it is difficult to know if an outcome is because the EM is doing well or because of the people around them. I could be wrong, but once you look high enough in the org chart to no longer see trios, this problem recedes.
The author really got me thinking about the timeless aspects of the role underlying fads. I have certainly noticed shifts in management practice at companies over my career, but I choose to believe the underlying philosophy is timeless, like the relationship between day to day software engineering and computer science.
I worry about the future of the EM discipline. Every decade or so, it seems like there is a push to eliminate the function altogether, and no one can agree on the skillset. And yet like junior engineers, this should be the function that grows future leadership. I don't understand why there is so much disdain for it.