Perhaps life is common (happened about a billion years ago here), but intelligent life is not (about 100,000 years ago, give or take).
Perhaps without FTL drive, it takes what explorers there might be a long time between (expensive!) visits, so sightings are rare. Without FTL, and without some kind of cold-sleep, a journey to the nearest stars pretty much takes a lifetime. A few would go, but not many.
It's too late (bedtime) for me to slap "Drake's equation" type numbers on this, but hopefully you get the idea. Maybe we've not seen anybody because they only visit any given planet every million years or so, and "they" equals 2 or 3 species local enough to even bother with that paltry schedule.
I'm not saying there is anybody out there, just that lacking pure freaking magic technology, it's a hell of a trip to make if they were. OTOH, if there is an outpost 100 light-years away, expect a visit in another 100 to 1000 years???
Perhaps without FTL drive, it takes what explorers there might be a long time between (expensive!) visits, so sightings are rare. Without FTL, and without some kind of cold-sleep, a journey to the nearest stars pretty much takes a lifetime. A few would go, but not many.
It's too late (bedtime) for me to slap "Drake's equation" type numbers on this, but hopefully you get the idea. Maybe we've not seen anybody because they only visit any given planet every million years or so, and "they" equals 2 or 3 species local enough to even bother with that paltry schedule.
I'm not saying there is anybody out there, just that lacking pure freaking magic technology, it's a hell of a trip to make if they were. OTOH, if there is an outpost 100 light-years away, expect a visit in another 100 to 1000 years???