heretic888, I can't even pretend to tell you that I am familiar with and understand all the ideas and concepts you present in this post. I am just a guitar player by trade, and a computer geek by hobby.
But, what you are describing, as near as I can figure, is the result of a rapid and severe evolutionary jump in the size of the human brain. I have been led to understand that a hundred thousand years ago ... give or take a hundred thousand years (or two) ... humans had some sort of random mutation/natural selection for a larger forebrain; somewhere along the line, our species' collective brains, got bigger.
Now, this, as I understand it, is the initial cause of homo sapiens rise to prominence. Without this evolutionary change, we would still be, more or less, a hairless ape.
But, if this did explain our dominance, why were we not dominant for so many tens of thousands of years after the mutation first became ubiquitous (is that the right word?).
upnorthkyosa, says it is language, which developmentally is explained, I think as you outline it. But, isn't there a gap there too? A time between the rise of language, and the rise of homo sapiens dominance?
I do believe our species dominance on the globe today (dominance, or is it infestation?) is contributed to by both our biological development of the brain, which drove the creation of spoken language, and then, a relatively short time ago, the written language. But, I still think it is agriculture that is the primary driver.
Agriculture created settled communities, and specialized roles in our community. It allowed for leisure time which could be used for other pursuits; such as building more clever tools. And, as food supplies could be increased and stored, populations were able to grow.
Of course, my preferred theory is really just the game 'Age of Empires'.