There's a far more charitable interpretation (and explanation) of this: broadness.
People who know too little don't know how to get to the happy path, let alone stay in there.
People who know too much know extensively where the happy path lies, it's neighborhood, how to go off-road out of the happy path and the dangers that lie therein.
People in the middle know how to get to the happy path and remain there, and know that steering away from the happy path leads to trouble and ambiguity. As they mastered the happy path then they feel unlimited confidence and arrogance.
People who know too little don't know how to get to the happy path, let alone stay in there.
People who know too much know extensively where the happy path lies, it's neighborhood, how to go off-road out of the happy path and the dangers that lie therein.
People in the middle know how to get to the happy path and remain there, and know that steering away from the happy path leads to trouble and ambiguity. As they mastered the happy path then they feel unlimited confidence and arrogance.