I reckon the universe is just teeming with life and we haven't been contacted yet as we are too lowly. We leave those guys on the islands alone and that's what aliens do to us. It only takes one civ to get to ai level representation, which is pretty much immorality.

Given not only the size of the universe but also the length of time it's been around I think we would be foolish to think we are alone.

There could be a point where we "discover" that everyone else lives in a city and we live on a tiny island.