Maybe it’s not a binary? Maybe managers should both be able to delegate AND occasionally put in the effort to learn how things are working on the ground? Otherwise after about 3 layers of hierarchy all of the signal is gone in a massive game of telephone, leaving high level executives completely clueless.
Delegation does not have to be because of a lack of knowledge. In fact, it seems like if one delegates for this reason its probably a sign of trouble to come. We delegate because of lack of time.
I guess its impossible for an executive to know ALL the details of the work they delegate, but I'd be willing to wager that executives who understand the details function better in the long run.
It certainly isn't tautological that executives be imbeciles about the businesses they run.