The historical setting at the moment of time matters a lot. Had the French Revolution not happened, he would've been yet another artillery lieutenant in the French army. In 1789 Jean Lannes was a dyer, Laurent de Gouvion Saint-Cyr was a paineter, Jean-Baptiste Jourdan worked in a clothing store, Jean-Baptiste Bessières was a barber, Guillaume Marie Anne Brune was a typesetter, Jean-Baptiste Kléber was an architect... et cetera, et cetera. But it happened, and lot of people got an impossible before chance to discover their dormant military talents.
The same is happening in Ukraine right now.
Prior to the war, Robert Brovdi (Magyar) was a local businessman on a periphery of Ukraine. Now he is a commander of probably the strongest drone force in the world.
Yes, but the point about Napoleon is that there was so much more about him than just military talents. The environment in which he flourished wasn't of his making, but he managed to grow in it and ended up impacting the whole world. Either directly by bringing the Napoleonic legal system to them with an army, or indirectly by inspiring or enabling nationalism, democratic ideas (power coming from the people, not deity), allowing the whole of Latin America to break free from the Spanish Empire by keeping the latter busy, etc etc.
Many people became successful militarily and even seized power afterwards during tumultuous times. Very few actually ended having such an impact worldwide.
And before any Brits come in with centuries old grudges, of course he did plenty of bad, most notably how he treated Haiti (which he at least acknowledged later in life).