It is hard to imagine that anyone who has not been immersed since birth in Islam could actually believe in all their craziness but people will PRETEND to believe in all sorts of things if it suits their purpose to do so. Even among those who call themselves Christians a sizable percentage simply claim the name because they benefit in some way by doing so.
I suspect that the incidence of pretended belief in Islam far exceeds what is observable among Christians and that is high enough. There must be a high percentage in Islam who would love to walk away from all of it but fear for their lives if they do.
“There must be a high percentage in Islam who would love to walk away from all of it but fear for their lives if they do.”
I’m sure that’s a factor. I understand there is an extreme penalty for leaving the faith.