Greetings,
This is a very interesting discussion, people.
In a strange way, I almost think Skye and the bit of the Qur'an she quotes have put their finger on it: if polytheism were true, then it's possible one of the gods could have become all-powerful and then monotheism would prevail.
How do believers know that this has not in fact happened?
I obviously come from the same perspective as barney, that all gods are man-made. I think one big reason that monotheism seems to be more popular than polytheism is that it's just simpler for people to understand. After all, simpler explanations are usually more immediately convincing than complex ones.
Peace