You make some very cogent points and make them well. But there are alternative ways of looking at it.
- It beg's the question "Why do I reject those other 529 gods?"
I reject the others specficially because I accept Christianity. I can neither prove my religion nor disprove (most) of the others, yet by accepting mine I must reject all others. I acknowledge I do this as a leap of faith, but that is different from being indoctrinated at a young age. I will agree with your over all point that most people just believe whatever they are told at a young age, but the more thoughtful people of any religion will often be able to bring forth real arguments for it. This of course is not proof, and many of these arguments involve sometimes personal experiences, but that is still very different from no good answer other than indoctrination.
Most of those gods have likely been created before your god had even first been mentioned.
Many religions will disagree with this. Literalists amoungst Christians and Jews, for instance, will beleive that God was known about since Adam with an unbroken chain of believers. The reasonable literalists will agree that God was first written about late in history, but that is different.
To those people, society did not move past older deities so much as some branched off to false religions and then some of those false religions faded away.
(I am not a literalist, but it is an alternate explanation)
If you follow the trend of gods, you realize that humanity has been generally moving away from polytheism towards monotheism.
True as a general rule, but first note that some polytheistic religions are still around, even in relatively highly educated populaces. Second, note that an alternate explanation is that God is trying to subtly guide humanity to the truth and moving to monotheism is man's response to this guidance. I am again not saying I personally believe this, but that is provides a different explanation.
You make excellent arguments which I respect, but there are other explanations for everything you bring up and I do not think they would provide much weight to someone who already believed one way or another.
[edit: fixed an omitted "not"]