We're not. And we may never be, let alone able to travel through space continuously while somehow maintaining generation after generation of life using a finite amount of resources that could travel with us. The paradox assumes so many things that are far from a given, to me it's confusing why such a great thinker couldn't see his own fallacious thinking. Maybe there is a ton of intelligent life out there that can barely get to the moon once or twice before giving up forever. That intelligent life would be like us, possibly dreaming of colonizing the next planet over while destroying itself. We could not, with current technology, possibly detect such life. We can barely detect earth like planets as is. The assumptions Fermi makes are simply too great for this idea to be compelling.