Maybe I'm projecting too much human behavior on unknowns, but we've pretty much come to the conclusion that we when run into an uncontacted tribe of humans, we try to stay completely hands off.
Perhaps we shouldn't discount the possibility that's a universal evolutionary stage, and that there's just some sort of 'prime directive' type thing keeping any life from contacting us yet?
Or perhaps the best move is to hide. With such a large range of time, almost any species you encounter will be either incredibly primitive (thus not so interesting, and not receptive to your signals), or tremendously advanced, and a serious existential threat. Faced with this choice, it's quite rational to avoid looking for the neighbors.
This doesn't really apply to the self-replication wave, but it is an argument against active SETI.
Perhaps we shouldn't discount the possibility that's a universal evolutionary stage, and that there's just some sort of 'prime directive' type thing keeping any life from contacting us yet?