The answer to the paradox, so many stars, so few civilizations, could be that civilizations have a short lifespan. Even a lifetime of a million years would not be enough to guarantee that there would be another civilization inside the Milky Way. Since our own glorious civilization is maybe five thousand years old, we probably have no idea what it would take to get another million years out of our system.
OT, but what's your tagline about?
There is another explanation. Consider how long we've been spewing forth our radio and TV radiation. If we make a large leap in technology, one that eliminates the inherent 'waste of radiation' in our communications programs, we would conceivably end our transmission status, at what entire length of emission period? We may indeed have many more advanced civilizations around us but are unable to detect them due to their efficiency level. [And for the record, since I've seen craft that are definitely not of this planet technology, I DO believe we are visited fairly regularly. It is the ingrained arrogance of the Fermi postulate that astounds one ... he assumed we at our current technological level were in the mainstream of civilizations possible for contact.]
The answer to the paradox, so many stars, so few civilizations, could be that civilizations have a short lifespan.Quite so. For example, the Earth gets pasted from time to time by asteroids and other space debris. When that happens, it can be quite serious, and has been quite serious.