They have only two destinies: struggle to reassert their independence as distinct cultures, or fall under the demographic tidal wave of Islam.
The jury is still out on what they will do. While it is true that the most popular first name for new babies born in Brussels is "Mohammed"...it is by no means a foregone conclusion that that will be the most common first name of 20 year olds in Brussels 20 years from now. History seldom takes a linear course.