I don't think people realize how quickly EM radiation falls off with distance, and how large the scale of "transmitters" would need be before we could detect.
Today we can finally, barely detect massive planets occluding suns, and we can only do this in our neighborhood of this galaxy.
Modulated communication from a source not at planetary scale is currently impossible for us to detect.
We need something much much bigger than the Arecibo telescope (RIP).
Arrays of coherent antennas can achieve gains equal to their total aperture, but spacing them out far apart does not help for communication receiver gain G/T. That technique only gives better angular resolution for imaging.
I also suspect that in time we will discover new mediums of communication that have better properties than the electromagnetic spectrum. Maybe when we listen on those mediums there will be a ton of chatter…
Within EM, gamma rays (highest frequencies) may be able to achieve sufficient spatial directivity for interstellar communication, but we'd have to be very lucky to have a beam pointed at us. Also currently our gamma ray receivers suck, and they have to be in space because our atmosphere largely blocks it.
On the other hand all those tech developments you pointed out we’ve only discovered and utilized in the last 100 years. Now imagine a civilization with 10 times that experience/time
Today we can finally, barely detect massive planets occluding suns, and we can only do this in our neighborhood of this galaxy.
Modulated communication from a source not at planetary scale is currently impossible for us to detect.
We need something much much bigger than the Arecibo telescope (RIP).
Arrays of coherent antennas can achieve gains equal to their total aperture, but spacing them out far apart does not help for communication receiver gain G/T. That technique only gives better angular resolution for imaging.