It's not even that space is too big. Time's too big. There's no reason to assume that the lifetime of technological civilization is more than a few hundred yea

It's not even that space is too big. Time's too big. There's no reason to assume that the lifetime of technological civilization is more than a few hundred years. By then they will have destroyed their own habitat and - despite some half-hearted (or even serious) attempts on colonizing different planets/planetoids - will have come to an inglorious end. Let's be generous and say that the lifetime of a technological civilization is a thousand years. That's the time that it can both send and receive signals from another technological civilization. The chance that one technological civilization is able to receive the signals of another is so vanishingly small as to be zero for all practical purposes.