LiveJournalist Blayne has an interesting analysis of why we may long for yesterday's future. His take on paleo-futurism seems to be rooted in the comfort of the nostalgic.
After the romantic innocence of retro-futurism is stripped away, you can see what drives our contemporary longing for imagined past-futures: Nostalgia, and a sincere desire for a return to familiar images of our past. It is in these familiar icons that we cope with our uncertain future. In my idle moments, its this desire "to return to a world that never really existed" that puts me at ease, regardless of what the buildings look like.