I think everybody agreed that when the original series had the Galactica come to present day Earth it was a total disaster, so what would be the dramatic purpose in having an ancient advanced race be the source of the Kobol colony? I mean there's no evidence of any such race -- and unless they cleaned up very, very carefully there would be evidence on the moon and other places in space -- so what does it get you? Isn't it a lot more interesting from an SF standpoint to have it be in our future, so that it says something about us?