I tend to evaluate this kind of question in two ways:
1) If the story is TRUE, what would we reasonably expect to see?
2) If the story is FALSE, what would we reasonably expect to see?
If the story is TRUE
If the story of Adam and Eve is true, we might expect that Adam and Eve would be able to pass their story onto their children, and that all cultures from then on would share a similar creation story. Early parents would have answered their children’s questions of “Where do we come from?” with the same story of Great Grandpa Adam and Great Grandma Eve and how the talking snake mucked everything up.
Additionally, if the Earth is, say, 6,000 years old, these stories only had to be passed down verbally for 2,500 years (or so) before being written down. This may seem like a long time, but with Biblical patriarchs like Adam, Methuselah and Noah living almost 1000 years each, the story should have a high level of continuity between the Garden of Eden and the time it was written down. There wouldn’t really be a need for a “special revelation” of the creation story, since it would be common knowledge from the beginning.
So if the Biblical creation story is true, details of it should have originated from the very beginning and all cultures would likely share knowledge of similar events.
If the story is FALSE
If false, we would likely see the story emerge from a single point and time, with the rest of the world being oblivious to the story up until that point.
What history bears out is numerous and varied creation stories from all over the world, and none are repeating the specifics of Adam and Eve, the talking serpent, original sin, and/or the expulsion from Eden.
While the early Jews may have shared some elements of their stories with their closest neighbors, their neighbors still told very different stories. And the more distant cultures, such as the Aztecs and Aborigines, remained completely oblivious to the Jewish story of creation.
So why don’t all people share the same creation story?
The fact that no creation story is shared by most cultures (or even a few of them) is at least consistent with the idea that no such history occurred. Every human desires to know how he got here and why he is here, so it’s difficult to imagine that this vital piece of information wasn’t the first story to be passed down to each new generation.
Even if every culture somehow managed to forget the story of its origins, it would’ve been nice of God to remind some or all cultures of the truth, and not just one.