Thanks for your answer!
I love the way you think about that and I agree for the most part!
Our technology of today may not be able to receive the signals. With trillions of places to look we may not be looking in the right places. It is only a question of time.
I also believe it's only a question of time. We only vary a little on the specific time frame! But who knows? An interesting signal could already been picked up and might just be waiting for the regarding data analysis to be "seen", it could happen today.