It’s possible—Fermi knew all this, and went ahead and invented the atomic bomb anyway.
Or maybe most planets that support life get thumped by an asteroid way too often for intelligent life to evolve…it’s all they can do to come up with a fresh batch of dinosaurs every couple million years. Or they get cooked by a gamma-ray burst from a nearby black hole the day after their inhabitants just learned to use fire.
By the way, a gamma ray burst would be one of the most serious ways humanity could suddenly cease to exist. They move at the speed of light, so there would be no advance warning, and it would cook off our whole atmosphere in about ten seconds, killing everything and leaving only Jesus sitting in Heaven thinking “Shit—I meant to go back there.”
But let’s not flatter ourselves—it’s entirely possible we’re surrounded by advanced civilizations, wise, powerful civilizations who have taken a careful look at us and decided “Courtesy call on these intercoursers? No way, Jose.”
This is because aliens can watch our TV shows. We’ve been broadcasting at the speed of light for seventy or so years now. Early TV wouldn’t have dissuaded the aliens from popping on by. They would have watched shows like Andy of Mayberry and The Avengers and thought to themselves “These are simple folk. They like to bake, make really obvious jokes, and spy. Load up the mother ship with live-forever pills and world peace machines and let’s contact them.”
Or they might have waited until the original Star Trek and said to themselves, “Holy crap, we need to head on over there and teach these people how to build an aerodynamically plausible space ship. Where are my saucer keys?”
But then our civilization advanced into the era of reality TV, probably just when the aliens were topping of the tanks on their starships for their trip to Earth. They started absorbing the lessons in My Great Big Racist Wedding. Or Too Fat for That Dress. They met the Duggars. They learned many of us were unshaven yickadoos who painted ducks for a living.
They watched a show featuring a man who ran around a big kitchen screaming at people who were trying to cook. “Why doesn’t anyone punch the Dickhead Chef?” they wondered. “If Earthlings were really civilized, someone would open up a can on that mofo.”
It wouldn’t all be negative impressions. The gay aliens would be wowed by Tim Gunn’s wardrobe. Aliens who fish would be on board with Wicked Tuna. But then they would switch to Naked and Afraid and think “Who wants to meet people with such blurry genitals?”
So they’re hesitating. Us watching shows like My Weighing as Much as A Forklift Life, or Fully Grown Men Who Still Build Tree Houses, or I Know Where I’d Like to Stick That Fish Tank is what’s keeping them from checking the tire pressure on their interstellar rovers and buckling up. And when they do show up, they may have nothing benevolent in mind.
They may just want to sucker punch Gordon Ramsay.