That's my point. If you look into the size of our galaxy, it is unreasonable to assume that we would have found life if it exists. The Milky Way is 100,000 light years away. So, if we sent out a message, and there was life that could actually understand and get that message, it would take 100,000 years for the message to reach them. Then, if they wanted to return the message, it would take at least another 100,000 years to get back to us. Your understanding of the limits of our technology is severely flawed. We aren't even close to being able to send messages that far without it taking thousands of years to get there.
It is utterly ridiculous to use our lack of finding extra terrestrial life as evidence that life doesn't exist outside earth. Our understanding of intergallactic space and our own milky way galaxy is far too limited to expect this reasonably.
Thus, there is absolutely no reason to think that life is not abundant throughout the cosmos. It's just that our concept of distance is so useless when speaking to the cosmos as a whole.
I mean, our entire galaxy could be inside a black hole, as black holes distort the laws of physics in a way that we don't nearly understand. And, that black hold could just be one in trillions of a much larger universe. Our understanding is far too limited to even count this out.