Because christianity's reform came from within the cultures that housed it, it was not imposed from outside. Muslims in the west are more "peaceful"? Really, that's what you're going with? Muslims in the west aren't becoming increasingly radicalized as their proportion of the population grows? Did you miss the past decade of history? Even if that was true (it isn't), if you hadn't noticed the vast majority of the muslim population in the world is not in the west. Muslims living here becoming slightly more accepting of western mores will not do shit to reform islam. The rest of the muslim world is in a vastly different course, and it is dragging the muslims of the west with it.
And the reform of christianity was not a peaceful, gradual process, it was triggered by massive suffering and civil wars. You may think it's selfish, but I have no idea why the west is somehow responsable for Islam's reform. Their religion has absolutely nothing to do with our cultures, in fact throughout history has ALWAYS been antagonistic to it.
It was not triggered by massive suffering and civil wars, the civil wars were caused due to the dissociation of the population believes than went more progressist opposing to the still conservativ religious power in place in Europe. Now that in Europe, the gouvernement are secular, there won't be this issue.
You can see in polls done on mulsims that the stance of western mulsims are more conservative than the stance of the population they live in but they are also more progressiv that their counterpart living in middle east. They are in-between. Concerning your proportion point, Balkan muslims are a majority in their country, they are still way more progressiv than the one living in Asia or middle-east.
Now ofc the muslims in the middle-east are not willing to reform their believes, so let's just let them realize by themselves that living according to sharia is shit. When we will stop interviene, they will only be able to realise than no one else is to blame for the shit they live in but themselves. I'm pretty sure that if the brotherhood in Egypt hadn't been overthrown by the army, they wouldn't have been reelected in the next election. Just as we can see a downfall of the islamist party in Tunisia.
The West is not responsible for islam reform on its soil but it has no choice, if we don't expulse muslims with european nationality or worse. The only way to have a cohesive society is to reform the believes of those who can't live peacefully in it because of their believes.
I want the Islam in Europe to be reformed for selfish reason, only because it is the easiest way to deal with the problem it is causing. It is easier (and more moral obviously) to reform than to kill, expulse or ban Islam in Europe. Islam already exists in Europe, this is a fact you have to face.