Have you two heard of Bosnia and Albania?
Albanian Muslims are mostly becoming atheists or going back to their Christian roots. Not only because of the Hoxha communist regime which prohibited religion, but Albanians remember the they were heavily oppressed during the Ottoman occupation when they were converted by force, hence Albanians hate Turks.
Albanians also identify with their ethnicity rather than religion before anything else, both Albanian Muslims and Christians believe to be the same ethnic group and share the same ethnic identity. It's a common saying amongst Albanian Muslims and Christians that the religion of Albanians is 'Albanianism'.
So for that to happen in Lebanon, Lebanese Christians and Muslims would have to share the same ethnic identity, then Lebanese Muslims might start abandoning Islam. But for now, both Lebanese Christians and Muslims believe to be different ethnic groups, the former believe to be native to the land who were heavily oppressed by Arabian Muslims while the latter proudly claim to be descendants of the violent Arabian conquerors who oppressed the former.