"You're saying that... Caliphate is to Islamic civilization what SM Stirling's Draka Domination is to Western civilization?" -George Carty
Not so long ago, the USSR filled a useful role for writers, especially lazy ones: it was the Evil Empire, a world-spanning colossus opposed to all things bright and beautiful. History marches on, though, and in the post-Soviet world the role of Evil Empire has passed to a new nation: The Randomid Caliphate.
The Randomid Caliphate is more common in future histories than alternate histories, for the relatively simple reason that it hasn't formed IOTL (at least not yet, according to exponents of this trope.)
Compare with Draka for a non-Islamic equivalent.
First and foremost: the Randomid Caliphate is mustache-twirlingly evil. Everything that offends modern sensibilities, everything that's an affront to the Universal Declaration of Human Rights, all the stuff that Muslims have to apologize for because somebody from their part of the world does it, or did it once, or is thought to have done it once - all of it's there. At a bare minimum, slavery is not only legal but mandatory (especially sex slavery; Randomids typically have the kind of harems that Victorians wrote pornography about.) So are hudud ordnances, burqas for the female persuasion, and dhimmitude imposed on
good and faithful Christians infidels. ("Infidel" is an expletive; it can be used interchangeably with entire classes of other nouns. Randomid English uses it a lot.)
The Randomid Caliphate is typically waging
war JIHAD against most of the world's other great powers, if not the entire planet at the same time. Slaves have to come from somewhere, after all. Without exception, it's their fault. They don't discuss that much, except to voice their dreams of a boot crushing a human infidel face - forever.
You would expect the Randomid Caliphate to completely dominate the world in every way. It doesn't. Expect a slur of Randomid technology in passing, as being inferior, obsolete or primitive in some way. Regardless of the natural resources in their bloated borders, or the fact that (courtesy of slavery) they can undercut labor costs anywhere on the planet, they aren't usually the world's major manufacturer either. Presumably the ongoing
war JIHAD ties up a lot of resources that could go towards export-oriented industry, and closes most of their obvious markets. For this reason, the Randomid Caliphate is a space-filling empire: it's much weaker than a state that large has any right to be.