Nice write , I agree to the thesis how ever strong the enemy is if the civilization and culture they brought is not advance eventually they will loose ( Mongols are also a good example, once they settle down)

But I have my doubt if Majority Muslim will ever convert, Christianity has lot of logical fallacies since most of them took Jesus as savior and ( there are lot of issues with church acquiring power and corrupt practices causing Reformation etc) . Modern West is all built on materialism but as rate of return decreases and progress is not bearing fruit as it did earlier eventually uncertainty and anxiety took over. Only their ability to fight ( out of fear or genetically?) and better weapon technology keeping them intact but the ship is sinking fast ( but its going to take lot of people with it) - People and Civilization needs Justice and Balance them afloat Only Progress and Rationality can go so far,