Not to mention, Islam thrives on tribalism.
If someone had told me right after 9/11 that President Bush would be hosting at the White House Shi'ite cleric Abdul Aziz al-Hakim, the head of the Supreme Council for the Islamic Revolution in Iraq, as the President did last week, I would not have ever believed it.
Islam IS tribalism.
It is a form of tribal governance.
In order for islam to really die out you would have to genetically conclusivly prove they are not really direct decendants of Mohamed. If there is no PERCIEVED blood connection there is less of an emotional wall.