But we're not talking about Qatar or Dubai in the 70's we're talking about Qatar/Dubai now, where the past couple of generations have had almost exactly the same kind of exposure to metal music. If a kid is going to be a creative metal guitarist he's going to be a creative metal guitarist, all he needs is a childhood where he's got access to metal music and a few friends around to direct him to the right bands, and a guitar. There's no good reason beyond that the kid shouldn't be good, and found a quality metal band later on.
The reason being it's "cultural" may be a truism or any ism you should wish, it's still the actual reason, and btw I mean it's cultural as in it's practically in the blood, in the genes. They're apparently 'not meant' to produce metal music in those areas, just like certain peoples are not meant to be especially athletic, or possess a rich cuisine, or have a renowned sense of humor. It's "cultural", but really it's beyond that.
Arabic music for e.g. as a whole has always been very limited compared to Western music. Yes they have the quarter tones etc but the music is rather redundant and formulaic and not nearly as rich as European music whether during classical times or modern. It isn't a cultural strength.