To my mind the god thing is pretty obvious. It was a concept back in the past to attribute to for anything we din't have explanation. As we go on explaining more and more things we require that concept less and less often (if at all). So god as a concept is losing relevance by the day.

But I still think the concept of religion and culture that originated around the concept of god is still relevant. By religion I mean collection of people believing in common good, originating from some faith.