I have to ask, how is there next to no Islam in Arabia or the adjacent areas? Is it just that Muslims are consistently at 49% of the local population while Christians are at 50%?
Ah, similar reasons why there isn't many christians there today. Muslims never had a long enough hold of the place to truly establish a lasting stronghold. Arabia was only fully converted around 1600. Current year is 1830. In addition there weren't many economic incentives for wealthy Muslims to stay there with the former wealth of the Roman empire under their control, by this point most have decided against jihading for it, (like how the British didn't truly care to set up a Christian government in the Holy Land in OTL)