Could there be a chance religion is merely man made-?

Sometimes I think about a scenario that happened when men and women still dwell in caves and naturally a human being will die and someone who is emotionally attached to this human will start bugging the heck out of the oldest human in their caveburbia, yes caveburbia…as to what happens now and where will his or her mate, or his or her little human end up going-?
Finally the oldest caveburbian blurts out, UP THERE IN THE SKY, THERE LIVES THE ONE WHO CREATED ALL, BUG THE HECK OUT OF HIM-!