History
should be more probable than otherwise. It's what actually happened, after all. The probability of Hitler* actually surviving all the assassination attempts he had to deal with just between 1933 and 1945 shouldn't be all that high
just considering the sheer quantity, and yet war games tend to not follow that stuff through, because removing Hitler removes a core part of what makes World War Two, World War Two, and carving out such a central part of that era just makes it less
fun.
In much the same way, playing up the probabilities of Islam actually rising and making it much more likely that Islam
doesn't succeed
or even appear at all removes a key part of what on earth actually makes the Early Middle Ages the Early Middle Ages. This dynamism being promoted makes it
less interesting by removing such an integral part of the era, and
less fun by removing such a
dynamic element from the Middle East.