Birth rates across the board indicate that much of Europe will likely become islamic in the not too distant future.
In a generation or so, I expect that Muslims will outnumber the European locals in particular areas where Muslim immigrants congregate, probably some of the larger cities. That's going to cause historic changes. What will France become when Paris has more Muslim residents than French?
The day is coming when large segments of the population will be angrily insisting that historic French culture has no more standing in France, or Dutch culture in the Netherlands, than Islamic culture does in either of those places.
Additionally, the same can be said of islam as a political/religious force worldwide i.e. becoming the dominant religion in the world.
It might look that way in Western Europe, which is being flooded by Muslim immigrants. I doubt if they will have the same kind of success in places like China.
If you woke up one day and found yourself in a situation where you were being given a choice to convert to islam or die, which would you choose?
I don't see it getting to that point for a long time, if ever. What's more likely is Europe going 'multicultural', where historic European cultures stop being the cultures of entire European countries and peoples, and become just more of the multiple cultures represented in Europe. When that happens, Western culture will lose its historic homeland and its heart.
So what I expect to happen in Europe isn't so much an ISIS-style forceable 'Islamification or death' as it is the growth of states-within-states in a number of European countries. Muslims will end up having their own schools, their own Islamic courts with jurisdiction over cases concerning Muslims, and so on. It's almost inevitable, as millions of Muslims move to Europe in search of a wealthier lifestyle, but with no intention of giving up their own cultures or assimilating. As their numbers grow, so will their power and their ability to institutionalize that culture alongside the cultures that are already there.