Aww, no alien empires yet

[Drashner1]

A somewhat more positive version of the Undetectability Conjecture might be that, as civilizations become more advanced, their technology becomes ever more efficient. And since most of the ways suggested to detect xenosophonts rely on detecting their waste energy - it may be that they produce so little waste energy that we simply don't have the means to pick it up (yet).

Tight beam and efficiently encoded transmissions, highly advanced drive systems that focus the majority of their energy into thrust and minimize 'glare' in other directions, and habitats that either absorb energy to Matrioshka levels or beyond or use some other design that is is even more efficient. Etc.

Just some thoughts,

Todd