It's possible, but I personally believe that any advanced aliens would have already been alerted to our existence. Wishful thinking, perhaps. So why haven't we heard anything from them? The same reason you don't drive halfway around the world to yell at a mound of fire ants about assimilating into the global economy. Edit: To elaborate (Edit2: Actually, mk managed to say this same thing with fewer words) - perhaps the phase of time between evolving human-level "intelligence", but still shy of the technology required to completely encrypt all electromagnetic communication/radiation* (for self defense) is typically very short, on the timescale of the universe. Maybe most civilizations completely ruin their home planet before developing the means to colonize elsewhere. And I'm not contradicting the article's premise, just pointing out that there are perhaps a huge number of unaccounted factors at play. *Just had a pretty decent idea for a protocol on this.