One of the saddest aspects of the teachings and practices of Islam is that those who leave Islam can be murdered for doing so, which makes obvious that many who want to leave the islamic culture don’t, for fear of being murdered, after all, why risk it all when you can just play along like you believe what the Koran says? The possibly fatal alternative makes this quite attractive, so I would bet that millions of so-called Muslims don’t believe the teachings of the Koran one bit, but go along merely to get along, to remain alive in their most religiously restrictive culture.
And we know that there are millions of Christians in the Middle East who are much persecuted, so how many millions more are there who keep their christian faith extremely private, for fear of such persecution? This is one reason why Islam will utltimately fail, because forced conversion never has, nor ever will, be a legitimate means to win the hearts and minds of humanity. People do not like tyranny, and that is what Islam brings.