One thing I realized I didn't answer was 'why'.
That really is the trippy part...somehow these ancient cultures knew that mankind would be at this kind of crossroads. Although, I think I understand why, and it's simple scientific extrapolation...same as the formula that tries to say how likely there are civilizations like ours out there in the universe. The answer is evolution. It's constant and they saw this, just as we do. We're evolving and it's friggin' amazing because we can objectively observe ourselves
while we perform the changes we anticipated. It's beyond a self-fulfilling prophecy...it's a mind-fuck of subjective/objective evolutionary processes that ties past, present and future into one continuum.
And on that note....