Inevitably we are working with a lot of assumptions. But the Drake equation is one of the simplest expressions of our reasoning in this area imaginable. There i

Inevitably we are working with a lot of assumptions. But the Drake equation is one of the simplest expressions of our reasoning in this area imaginable. There is nothing contrived about the equation itself. You might choose to put in different variables, but the result would be the same. At this point we do have a much better idea about the individual factors than we had when Frank Drake first wrote it down. We now know that planets are common. We know that tool-using intelligences arose independently several times on our planet, our civilization just happens to be the first on the local stage. We know that AI and nano technology have the potential to vastly increase the amount of time during which civilizations have a detectable output (hence the drone argument). We know there is nothing in principle preventing a civilization from colonizing the galaxy, even if speed-of-light restrictions always apply. So the argument goes that some species should already have done that. Given the age of the universe, it also seems unlikely that we're simply one of the first civilizations to arise. While you can easily argue that it's all useless speculation as long as we don't know the exact value of every single factor, the sheer volume of scenarios pointing to the WTF-ness of the Fermi Paradox should absolutely bother us. We're not exactly a cautious or rational civilization (yet), so the odds of us ignoring something fundamental in this area might be quite high.