Season 2.. brother Cavil said they left Caprica, they gave up their endeavours, and now we know they're looking for Earth.
So why doesn't the fleet simply.. go back to Caprica? I say let the Cylons find Earth, there's a chance either A) they will never find it, B) Earth could destroy the cylons, C) Earth could be baron or unpopulated for some reason, or not even exist. Either way they want to make it their new home. So, since the cylons are going far away never to return, why wouldn't the fleet turn back?
Obviously for the sake of the show they can't, but let's assume the show was reality and not a tv show.