Short answer:

History doesn't have a category: "inevitable", but one can say that the turmoil and intentional policy of French revolutionary government opened a path for ambitious young military men -of whom Napoleon was just one of many. At the same time the regime lacked sufficient legitimacy and coercive power to restrain these rising generals, a problem for Republics as old as Caesar.

Discussion:

History at the most granular level of detail is the interaction of millions of people, their spiritual, intellectual and material culture, with all sorts of intruding events-- failed harvests, diseases, accidents, discoveries of new resources and technologies. We never get to do "history experiments" -- eg playing back the history from the same starting point with slightly varied conditions-- but given the intensely noisy character of the problem it's easy to bet against anything happening twice exactly the same way. If the late 18th century were "replayed" a dozen times, in one of these scenarios Napoleon might choke on a peach pit, in another he might piss off someone powerful (like, perhaps, Paul Barras) at an inopportune time, in another, he gets sick in Egypt and dies. He was a man with talent, charisma and ambition, but that isn't so unusual for the period. There were lots of young officers with these qualities-- Napoleon's star rises because a lot of things go right for him. And as his star climbs, his ego grows with it-- had some other young officer fed on early success, he might have grown a comparable amour propre.

When it comes to Napoleon's rise, the French regime was actively looking for aggressive young generals, and Bonaparte was only one of several who rose in Lazare Carnot's system of "careers open to talent". One of the others, General Hoche, was a man of perhaps comparable talents to Bonaparte; Hoche dies very young, probably of tuberculosis. If things were only slightly different, perhaps Hoche lives, Bonaparte dies, and it's his story we talk about. Or a third young ambitious general: Pichegru who is killed after a failed insurrection against Napoleon.

What _is_ repeatable in history is that a certain kind of civil chaos is a fertile ground for a military man to rise, and that these conditions were present in France. So while Napoleon wasn't "inevitable" -- no one and nothing is in history, save death-- the emergence of such a kind of figure was more likely than at other times.

Other European nations, with established aristocracies, had much less room for an ambitious young man to rise in this fashion. Napoleon drew a parallel between himself and Frederick the Great-- but of course Frederick didn't "rise", he he inherited. Every once in a while a man of great talent and ambition will inherit a throne and try to, say, gain an Empire for a small kingdom, but heirs by their nature tend not to be particularly ambitious. To find a commoner rising to great military power at another time in Europe-- its not often. One example would be Albrecht von Wallenstein, a military entrepreneur of the Thirty Years' War -- and the limit to his career (the Emperor grows wary of Wallenstein's ambition, and has him assassinated), illustrates why such men don't rise so easily in settings with a more robust leadership jealous of its power.

So I'd take a pass on any notion of "greater" and "lesser" men, and think more about the structure of society and the robustness of political regimes to challenge. Which conditions promote the rise of the ambitious? Which retard them? One can look at the situation in Africa shortly after independence where the continent saw many military coups d'etat: this suggests something in common about social conditions which make the rise of a strongman more likely.

Similarly, one should look at why Napoleon's Coup Brumaire was welcomed, and why important French elites - including Ancien Regime aristocrats like Talleyrand, and ferocious revolutionaries like Fouché and Carnot-- supported him. To a significant extent, Napoleon's star rose because he was substantially "an answer" to problems for many constituencies in France. In that sense one can draw a parallel between Napoleon and Vladimir Putin -- who makes clearer that in an unsettled time, a man unaligned may be mistaken by by the powerful as being a useful tool of their ambitions. Paul Barras and Boris Berezovsky learned similar lessons about such assumptions.

​

Sources:

Johnson, Thomas H., et al. “Explaining African Military Coups D'Etat, 1960-1982.” The American Political Science Review, vol. 78, no. 3, 1984, pp. 622–640.

DWYER, PHILIP G. “NAPOLEON AND THE FOUNDATION OF THE EMPIRE.” The Historical Journal, vol. 53, no. 2, 2010, pp. 339–358.

Wolloch, Isser. "Napoleon and his Collaborators: The Making of a Dictatorship", (W.W. Norton:2001. )