Believing that all of them exist or existed in the minds of some people is not a far stretch. Yet, it is the ONE God that is a reality.
How is believing in more than one god a stretch more than believing in one? Seriously?
The universe is too coordinated in its complexity to have more gods than the One controlling it.
Let's say I believe the universe is so complex it requires more than one god to look after it. My reality is just as valid as yours.