If I've seen absolutely no evidence of something for 47 years then why would I believe it? I've no evidence that there's no fairies at the bottom of the garden apart from the fact that absolutely no-one has ever seen them.
Belief in god primarily derives from peoples inability to explain their origin or the world around them. It's an easy cop-out to attribute it to a mystical higher being. There's plenty of religious people who deny evolution despite the hard evidence. So it's more believable that someone made everything in 6 days, put two people on the earth who then had two sons whose wives mysteriously appeared from nowhere as there's no explanation of that? Someone started a great con trick with that nonsense.