First, sorry for the late response. I haven't had a lot of time on my hands lately.

Second, wow you really seem to have thought long about this subject. I hope I can cite you for it if needed in the future because I agree with everything you've written. One thing though. I do not believe the only reason we changed to monotheism was because it would be easier to worship one god instead of many. That's not how I'd advocate for my god, anyways.

I have a little trouble seeing how the invention of the wheel, agriculture and alike have affected our religious views.

Surely, when civilizations form, war of territories are bound to happen and such a community could have formed an "us vs. them" mentality, giving nourishment to monotheism, but please give me your explanation.

The way I see this evolution of religion through time is because of the human desire to have power. When we changed from animism to polytheism, some had to be the connections to "The higher powers", thus creating an upper class of those who were able to communicate or were servants of these powers.

Again, when we changed to monotheism, I believe it was because a smaller elite wanted to gain more power, allowing only one power to fewer servants, who then became an even higher class.

Now, when we turn to atheism, I have two theories:

One, we figured out we didn't want to be second to power, and pushed over the deity, or

Two, our technology became so advanced that we have begun to realize that there's no room for a deity in our universe.