[IAmBroom]

Counterpoint: Name a great victory where top leadership mattered very little.

Or, for that matter, a massive upset where top leadership did not truly contribute significantly.

The "fog of war", AFAIK, tends to refer to general breakdown of communication (as you noted), but even fully localized control (terrorist cells, I suppose) are not highly effectual without coordination and informed assessment of the overall picture. The horrific triple (almost quadruple) attacks of 9/11/2001 would have been greatly diminished, probably by 2/3, if the attacks weren't centrally coordinated.

Wartime is exactly when centralized control is most needed.

[tikhonj]

Leaders can matter—a lot—even if they do not exercise granular, top-down control. They can provide the right context and motivation, articulate high-level aims, resolve issues and create the kinds of systems and cultures that do not need explicit direction.

A great illustration of this idea in context is Andrew Gordon's book on the Battle of Jutland, The Rules of the Game[1]. He mostly contrasts the leadership philosophies in the British Navy shortly before and during the Battle of Jutland. The British Navy became very top-down and procedure-oriented during peacetime, which did not generalize well to operating in battle.

[1]: https://www.goodreads.com/book/show/354137.Rules_of_the_Game