While on a treadmill at a fitness club, I noticed a woman reading a book with a chapter title, "God Is Everywhere." I asked her how she knew God was everywhere. She said that she knew because she had a strong sense of him. I said that I had the strongest sense imagionable of Santa Clause when I was 8. She said, THAT'S NOT THE SAME THING!
However, it is the same thing, is it not? In both cases, the entities are supernatural. In both cases, we have been told by elders to believe in impossible magic with zero empirical evidence. Doesn't it follow then that, just like a child must grow up one day to accept there is no Santa Clause, adults need to come to terms with the truth about their imaginary friend in the sky?
If the concept of God that you are considering is simply an adult version of Santa Claus, then you are correct that just as a child must one accept that there is no Santa Claus, so an adult needs to come to terms with the truth that their is no adult version of Santa Clause, what you call "their imaginary friend in the sky." However, there are concepts of God which are not simply adult versions of Santa Claus, and so even if adults should give up their belief in a God that is an adult version of Santa Claus, it does not follow that they should give up their belief in a different concept of God.