No, that's not why. Here's why-
Scientists are discovering that a part of religious peoples brains, the temporal lobes, and other specific parts of their brains, are overly-sensitized, faulty and under-evolved.
Specific parts of religious peoples brains haven't evolved as fast as the brains of Atheists and people who don't believe in god and religion. Parts of many religious peoples brains are stuck in the Stone Age and Bronze Age.
But other parts of their brain work fine. That's why you will find religious people in all walks of life.
With many people, believing in God is a combination of both nature and nurture, genetic and learned. Every individual is different.
Parts of many religious peoples brain hardware are old and outdated and permanently stuck in the Stone Age-Bronze Age and can't be updated. They are "science-blind", in many ways, the same way a person is color-blind. So they continue to believe in an ancient, primitive, make-believe, nonexistent, fairy tale Santa-God.
Take a look at these-
http://www.youtube.com/watch?v=8YPOTaUyvA0
http://www.youtube.com/watch?v=rQ_DVN5zrXk&feature=autoplay&list=PL9F5940B056BAD025&lf=results_video&playnext=2
http://www.npr.org/templates/story/story.php?storyId=104291534
http://www.livescience.com/3366-scientists-god-brain.html