I could see several viewpoints, but it makes sense to me that a belief in a god, in a shared contextual framework, would provide the scaffolding by which a community can work together, grow, trade, share, defend against outsiders, and many more things that could lead to a higher likelihood of genetic propagation.
I'm in the middle of reading a great book called Sapiens: a brief history of humankind by Yuval Noah Harari. A big part of the book is the assertion that humankind was able to develop past a family or tiny tribe based on it's unique ability to create shared myths. The belief in capitalism, religion, LLC's, Devine Right, or any mental construct allows some agreed upon principals by which people in a society can come together and build, work or grow together. Money for example is a shared myth, it is only worth something because of the social and political constructs that have created its concept. And so long as we all agree that money is something, I can sell my guitar to someone I don't know and have faith that the money I receive in return is an adequate exchange. Likewise, the shared myth of any specific god or religion provides the framework for people who have not met to work together and expand society. I recommend the book highly, it's very interesting and well researched. There are some ideas he proposes I agree with and others I don't but regardless he puts together some truly interesting concepts to think about.
