Having made the same observation as you, I always preferred the formulation in https://en.wikipedia.org/wiki/Ringelmann_effect. Although the Wikipedia article lists "loss of motivation" as a cause, it originally focussed more on coordination problems growing with group size–sort of a reverse Metcalf'.

In that sense it avoids the lazy cynicism of writing off whole groups of people as stupid or unmotivated (i. e. all of Dilbert). Instead, it's a starting point to consider how much we can still improve what's arguably humanity's claim to fame, the ability to cooperate.