Many kids are raised in the faith of their parents and enter adulthood remaining a member of that faith. Yes, the sharing of ideas and exposure to different cultures can influence a person, but many remain in their faith. Some who remain accept some of the ideas they have been exposed to and thus they and their religion morph into something different. Some, like me, leave their religion behind. That is not true for everyone though. There are those who remain steadfast in 'traditional' beliefs and practices.

Too many Muslims for Islam to be erased in our time. I suspect it will morph and change, but it will remain - kinda like Christianity. Religions are slow to change, but they do.