Religion is a social phenomenon. It is the codified, formalised expression of a given group's customs and rules (which is why writing it down and letting people

Religion is a social phenomenon. It is the codified, formalised expression of a given group's customs and rules (which is why writing it down and letting people outside a narrow priesthood have access to it is generally a disaster - it makes it very hard for the religion to change as the culture does, because there's always someone ready to take the words seriously). Successful religions tend to be those with a significant social aspect. Even churches that are nominally the same religion often have deep divides across the social groups. With the opportunities young people have now to explore beyond their immediate group, both physically and mentally, it's hardly surprising that religion won't take.