Wherever you have a Muslim super-majority, ignorance, poverty, violence, and sub-standards of living accompany it. In addition, much of today's armed conflicts directly involve Islam. Without vast oil revenues and liberal appeasement throughout Europe, you would have a "civilization" living in tents stabbing each other with spears. Modern Muslim nations contribute little, if anything at all, to today's society.
Then again, I'm not worried about the numbers...let the uneducated hordes come in. Outnumbered western nations have conquered entire countries of where these hordes come from. They don't vote, are ignorant, and are nothing more than a mob...a mob that can be put down if it gets out of hand.