From Ross Pomeroy at Space.com:
10. Nobody is transmitting. Instead, everybody may be listening. That’s basically how it is here on Earth. Apart from a few paltry efforts to broadcast strong signals over a narrow frequency band towards the stars above, we’ve barely made our presence known in the universe. In fact, if aliens have radio telescopes similar to what we have on Earth, our television and radio broadcasts would only be detectable up to 0.3 light-years away. That distance doesn’t even transcend the farthest reaches of our solar system.
11. Earth is deliberately not being contacted. On Earth, we have policies about contacting indigenous peoples; it’s possible that the same thing could be happening with us. Just like in Star Trek, advanced alien societies may enforce rules that limit contact only to species that attain a lofty degree of technological or cultural evolution.More.
How about, the aliens are dead drunk at the bottom of the stairs? Look, it’s okay. We do not care. We honestly do not. We can sort of understand it. We would rather tey be dead drynk at the bottom of th stairs than not be out there.
See also: How do we grapple with the idea that ET might not be out there?