I think the great man theory is less applicable to the political realm than to the realm of ideas. Intellectual genius is categorically above ordinary human capabilities, but when it comes to wars, revolutions, mass movements and the like, it is more headless.
Think of an ant colony. Each single ant has one job, and by every one of them doing it without fail the whole machine of the colony keeps running. Meanwhile the queen just lays there and shits out eggs.
It's true that there are sometimes the "brains" of the operation who operates the collective human machine, Napoleon to his Grande Armée, who did all the heavy lifting? Who procured all the materials? Who did all the fighting? Napoleon without his army is Napoleon sitting on Elba island chubby and brooding.
Napoleon, as the quintessential example of a Great Man according to Hegel, also got lucky. He rose through the French military's ranks rapidly and became a high ranking officer in his mid to late 20s, an unprecedented event, because all the old French military officers were from the nobility and were either killed or relieved of their positions. He was not a demigod.
Similar for Hitler (not to imply he is "great" in the sense of approvable), who was produced by the Nazi party rather than its undisputed dominator and who rode atop the crest of a wave of resentment in Germany's masses.
Finally every great man has been enabled by social structures that supported that position, he did not create his own reality like a God, but was allowed to do what he did. They were allowed to have POWER, if they weren't, they would have never happened and would have been one more of the masses
Also, if there is a Great Man theory there is also a Terrible Man theory, those individuals who fucked everything up.
Who knows what Caligula might have done had he never been assassinated, what stupid wars.
Look now at Trump, who is a complete fraud in everything he does. He is exceptional for all the wrong reasons. By the time he left office America was nearly set to implode.