I don't think it matters, really. If Islam had never existed, something else would have and things would be different but no better. The trouble with humanity is, as Christopher Hitchens once put it, our adrenal glands are too big and our frontal lobes are too small. George Carlin got it right too. A person of average intelligence isn't really very smart, these are people who have difficulty understanding the material in a standard grade 12 curriculum, and by definition half of us aren't even that smart.