What someone else at the Wall Street Journal wrote about religious brainwashing.

People generally believe what they were taught to believe as children. If educated adults were to be evangelized today, having never been exposed to Christianity (or Mormonism, etc.), they would be baffled that anyone would join.

We're all aware the dead don't come back to life, that there's no massive place where the dead now live, and so on. As we understand more and more of how the world and the cosmos work, we understand also that there's no longer a place for supernatural stories and explanations. Then these less-supernatural people become parents and are less likely to pass along these remnants of a pre-scientific understanding.