No ET! Ever?

[Aoi Magi]

I can imagine us being alone quite easily, but I like the "dark forest" idea better. The universe might be full of life, but the basic rules are same, that is, resource is limited, and own survival takes priority, so if you are an advanced civilization, it is much better and safer for you to wipe out the competition before they do the same to you, and if you don't know the capabilities of the other civilization yet, you'd try to stay hidden till you are sure you are not the weakest. So maybe all intelligent civilizations are hiding from each other, and maybe those who tried to make themselves known got wiped out?

The counter-balance to "Dark Forest" is Greg Bear's "Forge of God". Xenophobic killer alien civilizations would pose a threat to all other worlds. They would face retribution from the empowered remnants of displaced species.

Yes they might, but that doesn't really increase the chances of communication, rather as more civilizations destroy each other, communication possibilities will only go down.