This is a follow-up to yesterday's post. As many of you pointed out in the comments, one would probably have to put Gary Gygax and Dave Arneson into the Newton/Einstein camp, in that the creation of role playing games was probably inevitable and would have happened at some point soon anyway. But there is a genuine case to be made that it was not inevitable - and even quite unlikely - that it should have ended up a fantasy game, and particularly one about exploring dungeons.
As will be evident to anyone (and, again, as most commenters pointed out yesterday), human beings like role playing, and will do it even with purportedly abstract games, or when on their own. Nobody who has ever played a video or board game can fail to notice that as soon as there is some character or item with which one can personally identify, people begin to act in accordance with that particular 'role' and to a certain extent assume it psychologically (if only for the duration of playing the game).
Insofar as this is true, I think we can safely say that at some point people would have come up with something along the lines of D&D even if Gygax and Arneson had never been born. It is only a very short leap from 'doing a voice' while guiding the battleship around the Monopoly board and haughtily demanding rent for a competitor landing on Old Kent Road, to actually role playing 'let's pretend to be 19th century property developers and make up complicated rules for the game'. It would have happened sooner or later.
However, it is really rather unusual that the first real role playing game worthy of the name happened to have an assumed fantasy setting rather than anything else. It seems to me that, all other things being equal, one would have expected the first role playing game to have emerged from historical wargames (as it did so, indirectly), and hence have something to do with either the Napoleonic era, World War I or World War II. In fact, I wouldn't be surprised if there turns out to be a large number of parallel universes in which 'D&D' is actually a Commando comics-style WWII 'special forces' RPG.
(Other possibilities that seem at least as, if not more, plausible than a fantasy setting for a first-ever RPG include something to do with sport, a specific historical era, colonisation, business tycoons, even biblical stories.)
Gygax and Arneson, in other words, also have a bit of the Gustave Eiffel about them. The concept of the role playing game was probably always going to be invented, but the fact that RPGs have become synonymous with a particular type of fantasy is surprising, in hindsight, and really has to be put down to fluke - or, being charitable, to a genuine flash of genius,.