@bythos in authors defense, those clothes, though historically innacurate, have kinda become whats common nowadays for fantasy arabian settings. For example you can go to one of the most famous adaptations of the arabian nights stories, disneys "aladdin", and im sure there are many others.
This is just what became the "popular norm" instead of whats accurate, kinda like after LOTR all elves in other works became tall, gracefull and supernaturally beautiful, while before that elves were generally more like gnomes, or hobbits.