There are next-to-no academic historians who do.

Certainly, they might say that a historical figure has a major effect on history, but the idea that, say, the French Revolution or World War II would have just not happened if Robespierre or Hitler had been stillborn is seriously devalued these days.

Suffice to say, that the causes of the French Revolution and World War II both went beyond the simple will of one man.

I bet there is. There are probably historians, even if it's a small minority, that believe in all sorts of strange theories.

It's so outdated that it would be hard to pass a viva if you did. So unless they somehow completely avoided it in their PhD thesis only to then come out with it afterwards, probably not. Then of course peer-review, getting work at a university, etc. Someone still following such old concepts wouldn't be a popular candidate.

We still see it a lot in amateur historian works though, in fact it's still very popular there. But I can't think of any recent works published by actual historians that maintain this -- though I can only go off of what I've come across in my own research which hasn't been looking for such a thing.

If there are, they're kind of going to be fringe historians or popular historians, probably older. The big reason why this doesn't really exist in the field anymore is that historians, through their work, have shown that the world is just too complex for any one person to control history in the sort of way that used to be attributed to people like Barbarossa or Charlemagne. Marxist theories of history have done a lot to show how the vagaries of things like geology can lead to bread riots in France right as the king's finances get exposed that are beyond the control of any individual. And for any individual's actions there are countless other's doing their own actions, sometimes in support, sometimes in opposition, sometimes in totally different spaces or overlapping spaces without concern of other's actions. History is just too complex.

Besides the great man type history, you also don't really see works like Gibbons' The Decline and Fall of the Roman Empire. The kind of history where you develop a grand theory to explain everything is just out fashion and recognized as too unrealistic of a pursuit. Now an academic might try and write a book that covered a topic over a length of time, like maybe US history for some period, or German colonialism in Africa, but it usually won't get more general than that b/c they have enough knowledge to realize the flaws and errors that get introduced when you have generalize more than that.

Some popular historians still write these books, but they're usually used to justify some kind of political goal or worldview and aren't really taken seriously b/c they reason backwards from a conclusion rather than forming a theory from evidence and arguing in support of a theory. They're the kind of books pundits might "write" and promote. They go through a print run and are pretty much never referred to again.

cf. Andrew Roberts and Napoleon.