I think they did it because it's interesting to juxtapose old and new, it's visually stimulating. But I also think they mix ancient and hi-tech because seriously, aren't the survivors supposed to be our ancestors? They come to earth and over time become the next set of gods--apollo, athena, etc. and all the rest? That seemed to be the theme of the original series--the fighter pilots even wore pharoah-like helmets. Then we seed the stars and create the next set of colonies and the next cycle.