The point is that probably 20% of the ICs at the company could diagnose the problem over a beer but management keeps such a stranglehold over access and narrative that only an overpaid consultant wearing a nice suit is acceptable politically.

Sure. Similarly, the US government "knew" about 9/11 and Pearl Harbour hours before the planes hit anything. But understanding which signals to pay attention to and make decisions upon is genuinely a hard challenge of leadership.

Agreed. But are you saying McKinsey is better at that?

For better or worse, McKinsey and outfits like them have an ability to package a given set of advice in a way that the needed audience will be more likely to heed. Partly because they can MBA the lingo, but also just from the imputed competence that comes from having spent a goddamn boatload on their brand name.

That makes sense, and is a really good example of organizational cognitive dissonance. https://en.wikipedia.org/wiki/Cognitive_dissonance