I prefer the "Lots of life, utterly separated by time and space, running into some version of the 'Great Filter'." Space is just too damned big, and the timesca

I prefer the "Lots of life, utterly separated by time and space, running into some version of the 'Great Filter'." Space is just too damned big, and the timescales involved in two way communication are too nasty. Maybe the solution is that any sufficiently advanced species either blows up, or stays focused entirely on what it can realistically communicate with 2-way (so incredibly close by, cosmically speaking).