Peace Lena, all
Let's suppose that there are many gods; each of these gods has his own creation.
There are 2 scenarios:
1- There is enough space to contain all these gods and their creations, so they don't have to interact or enter in competition, so each god can express his complete authority over his own creation.
But then we have to consider that the creator of this space (where these gods evolve) is like a supergod compared to these gods, he is much more powerful that he is able to create a space to contain all these gods/creations.
These gods then cannot be considered as gods anymore, because they don't have full control, and are only allowed to exist by the power the real god the creator of all.
2- These gods co-exist and share the same space for their creations; none of them can have full control all the time without it creating chaos as each one would want to be all powerfull all the time, or in the case of co-management it will nullify/suspend their super attributes at least for sometime; they are not gods anymore.
furthermore, the creation of the space in which these gods evolve bring us again to the implication of the existence of a god much more powerful who can create a space to contain all these gods and their powers.
We come always to the conclusion that there must be only one supreme creator.

Need to trace back on "Why" people created this (imagery) gods / deities in the first place...
Thus it brings out "Polytheism" and then came "Monotheism" as a reaction...
It goes back to the conflict among the 'priestly class'..
To seek peace, wealth and power division among themselves they created different gods/deities as thus there will be enough gods/deities to specialize themselves with...
One group become the priest of "Penis god" (for example) the other "Vagina god", the other "Sky god" and then "Sun god" etc.. etc.. etc..
Where each priestly group have their own authority over rites, temple design (including representation of deity/deities) and of course the most important thing is the 'minimum amount of donation' to enter the temple and/or receive the priest's.... erggh I mean.... the god's blessing (which 'channeled' through the priest).
The pattern is clearly evident within today Hinduism..
So it seems; due to the baby boomers period (now over 1Billion population in India alone) there's now an oversupply of 'priest'.. especially the priest who specialize in a deity named Krishn..
Thus to create "Peace and Authority Division" among themselves they start to re-specialize by the color of Krishn .
One become the priest of Blue Krishn, the other Black Krishn, Red Krishn.. so on and so forth..
The argument goes; since Krishn is a god he can color himself with any color that he choose.
Each "Color" of Krishn has it's own set of priest, temple (of course this is the most important thing) and rites (the 2nd most important thing).. and minimum donation (The upper most important thing)
Perhaps 1000 years from now, they will start running out of Color and they will start re-specializing in Krishn's pose!
Blue Krishn Running, Red Krishn Sitting, Orange Krishn playing Football etc...
And thus Polytheism was born.. and new deities / god shall continue to be born to cater the needs of growing number of priests...
Salam / Peace