Why Middle East?

[mediamogul]

The gods were born in the Middle East.

The earliest evidence of ritual to date was found in Botswana a few years ago, going back to roughly 70,000 BC.

Christianity especially is steeped in the philosophical thinking associated with the Greeks. I think you are right in terms of Zoroastrianism being the first monotheistic religion in the narrow sense (the common ancestor) but the philosophical underpinnings of Christianity and Islam are firmly Greek. Catholicism essentially hijacked Aristotelian ethics, Platonic metaphysics in the sense of a more perfect world beyond this one, and a thoroughly Greek dualism in terms of the separation between body and "soul". Many civilizations had animistic beliefs and superstitions regarding the natural world and their "gods" but I want to say that religion in the sense that we understand it was institutionalized in monotheism in the Middle East. Dawkins described Islam and Christianity as "carnivore" and Buddhism as "herbivore". Middle Eastern monotheism had a seriously aggressive bent to it which can account for it's spread within the "memeplex" of competing religious ideas. This could also account for it's "catchiness".