Hmmmm---I wonder if the "Muslim world" made most of its progress when the Kurds were in charge (Saladin) and ceased to do so when the Arabs took over. I haven't studied the history of the rise and stagnation of Islam enough to know.
The Kurds and the Ottoman Empire -- even if the Kurds and Turks don't get along.
I'm more and more convinced that the problem with Islam isn't Islam, but the Arabs.