1. The difference is that the Taliban has strong religious values as a foundation (unlike modern day christians), so they will never change, they will have to be killed off
2. I think its the opposite that will happen, there are muslims immigrating to the west all the time and the form islamic communities. Their birth rate is positive while the birth rate of westerners is in decline, so at some point Muslims will outnumber Christians, from there they will start practicing extremism and a civil war may break out, and I believe they would win because again their belief is stronger
Its like a Viking Vs and Englishman, the vikings believed that they only went to their heaven if they died in battle, so they fought with a level of carelessness and fervor that Englishmen could not replicate, same with modern day Christians and Muslims, most Christians today profess all this "I believe in Jesus" shit but they are really just cowards when shit hits the fan, whereas Muslims are less afraid to die and willing to go to extremes
For example, crashing a plane into a building and killing yourself just to send a message
Christians today aren't on that level, their belief in their God isn't that strong
This is why I believe in the end the West is going to lose, all Muslims have to do is immigrate at let the power of demograhpics over generations play in their favor