In the thread of this thought, to search for intelligent life off-planet sort of misses the point, doesn't it? Here we have an intelligent species with a common ancestor, which we may assume to be easier to communicate with than an extra-terrestrial being. And we have hardly begun to attempt to communicate with our earthly neighbor in a meaningful way, but we have projects probing the cosmos for signals from space.
Given the limitations of their physical bodies, would they even be capable of developing any sophisticated instruments at all?
Point being, intelligence may not be the limiting factor for extraterrestrial communication at all.
Are you asking why I’d assume that they don’t have the biological ability to send electromagnetic communication signals?
If that’s not what you’re asking, I don’t understand how else they’d send signals through space without sophisticated instruments capable of transmitting powerful signals.
Please clarify.