I'll buy that. However, I expect that more often the life is specialized and unintelligent. Life on Earth can be found at extremes. My guess is that once a planet has it, it becomes hard to shake it entirely. I expect that if Mars ever did have life, pockets of life can be found there today. We could be extinct or astronomically invisible in a relatively short time, meaning that our intelligent imprint was just a blink.
We will see I guess. Where does everyone stand on the 'Broadcast our existence' vs 'be super duper quiet and try to maintain a low interstellar profile?' Personally I think we should try to not pollute the long range radio frequencies and just listen very intently until we find something. Having the ability to dictate the terms of first contact would most likely be in our favor.
Odds are that the stuff we broadcast is so attenuated at about 2 light years nobody will hear the signal anyway. Add on that there 1. has to be someone who can listen 2. they need the equipment to hear us and 3. they need to be listening in our direction. Think where we were 100-150 years ago. Now think about where we are going to be in 100+ more years. The odds area against us in the near-present, but one day I hope we find something out there.
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.
Your argument for the no-contact is : -Alien are way beyond us (ants). But hey, we study ants at least. That's called the 'Zoo scenario' (we're the pet). Some other arguments are: -They stay in their Dyson sphere, happy with their lives without any need to conquer the galaxy. -They communicate by means beyond our understanding (Snowden used that argument by saying that aliens use encryption) - We're part of the alien: Earth was randomly seeded with life because aliens found it the fastest way to populate the galaxy. The best one: - Everyone stay silent, because there are some killer robots or something out there. (Ancient Aliens need a ton of episodes about that) Other arguments are mostly about death: -Life is ultra rare -Life is fragile ( this article argument's) -Sentience is doomed (to kill itself before take off) All this is so fun