I'm about halfway through this book, and it's great, but I don't agree that belief in God is a neurosis. Let's suppose for the sake of argument that there is a God who wishes to be known, insofar as that's possible.
The episode of Ikhnaton is really remarkable. No sooner than Egypt became a world power, expanding its borders through conquest, monotheism appears out of nowhere. Suddenly this guy has a revelation and decides there's only one God. He converts the whole country by force, but it only lasts twenty years or so. Some true believers went and settled in Canaan, and it became Judaism.
I haven't read the whole thing, but Zoroastrianism hasn't been mentioned yet, maybe that was another sort of monotheism exported from Egypt onto different soil.
Here's a coincidence, I read a Christian interpretation of the fall of the Roman Empire, saying, well, the whole purpose of the Roman Empire was so that Chrisianity could spread. Which I thought was an interesting take, but it wasn't an idea that I would assert with conviction. But the Ikhnaton episode, occurring just after Egypt became an empire, lends plausibility to the idea.