I agree I think that was part of the plan. If they could show themselves as successful against the west, they thought all good Muslims would be as blood thirsty as them and rapidly join their ranks. Fortunately, it seems that most Muslims are bad muslims and don't have enough desire to kill and maim the innocent to do anything more than support Al Quaeda financially.
Enough followers and they could start taking over other middle east governments and spread their madness to their subjects. Then having united the middle east under Islamofasism, they could begin a war with the west in earnest.