Iran is going through a process that will eventually separate the church from the state, and ensure the people have full democracy.
Islam is specifically designed to BE the state as well as the church, so that isn't going to happen without some fundamental changes. And Islam's appeal to much of the world is its utter certainty and resistance to change. It ain't going to happen anytime soon.
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Perhaps I didn't emphasise enough, so I'll repeat that it may take 400 years but eventually the power of the church, in this case Islam, will decline and be replaced by a democratic system. It will not be "anytime soon" that is for sure. But if you went back 400 years in England you would not have even contemplated the thought that both the church and monarchy's power would be disappated by the common folk, the peasants. Same in France, until 1789 no-one believed there could be a realistic alternative to the power of the main Estates, the Catholic Church and the monarchy, along with the aristocracy. But in both cases it eventually happened.
Islam is not the be all and end all. As the people look for a system whereby they can be valued as individuals, with full human rights, justice, wealth, and democracy - having a true say in there lives and not being led by clerics - then the power / attraction of Islam will fade as their abuse of power becomes all too obvious as it has in Iran.
Islam and Christainity will still exist as faiths and religions, but not as political powers. Secular societies will develop around the Islamic world, as it has already in Turkey, although there it has a long way to go before it is democratic.