modeler //Children are being pragmatic, they may as well go along with their parents fantasy.//
That is a very astute observation.
Much of what can be adopted despite the reality that is obvious to common sense is about choosing to fit in. Religion has always been perpetuated by the young accepting the dominant paradigm. (Along with killing anyone who didn't conform.)
Traditionally the churches ensured that they were in control of what people were allowed to say. Criticism of the church was quashed by blasphemy and heresy laws applied ruthlessly to maintain the dictatorship of the oligarchy.
In a modern world flooded with high quality information, religion becomes increasingly recognised as an anachronism.
Without being born into an environment where everyone displayes universal reverence to ancient irrational myths, the growing minds of today's children are far less susceptible to the concept of any of the hundreds of thousands of god, fairies, angels or even Santa Clause for that matter.
Moreover the modern child in a developed country is born into a world where so much is going on that the notion of religion is becoming extremely diluted.
They know the technological world is a product of science and knowledge continues to exponentiate. Meanwhile religion offers nothing more tangible than an unlikely to be fulfilled promise of a better life after you die.