This is common in scifi, in Dune the earth is long forgotten (ignoring crappy prequels), in Revelation Space it's known but all the interesting stuff is happeni

This is common in scifi, in Dune the earth is long forgotten (ignoring crappy prequels), in Revelation Space it's known but all the interesting stuff is happening elsewhere. I think it's more about trying to avoid explaining how we get from today to the time of the story, which involves some always wrong predictions of the future. Contrast with something like star trek where the Eugenics War apparently ended 22 years ago.