"Yet in UK, Christian faith schools are massively over-subscribed and people lie about their beliefs (or lack of) to get their kids the benefit."

That's not because there's some drift towards religion by the child-bearing populace, but because faith schools are considered superior to state schools. They may be so, but that's got sod all to do with divine influence and more to do with the fact faith schools discriminate against poorer or less able pupils (see data here).

Faith schools are divisive and retrogressive; they don't encourage integration, tolerance or allow their pupils to mix with people whose views might not be their own. This is not good for the pupils or greater society.