Science fiction generates compelling, if depressing, answers to why we haven't found alien intelligence.
"The thing that makes the Fermi Paradox interesting for SF is that like the speed of light, you have to have an answer for it. It can be any answer you like, but it has to answer it."
Tor compiles a list of possible solutions to the Fermi paradox, including:
—The aliens will arrive any minute
—The aliens, who planted us as a crop, will arrive any minute for the harvest
—The aliens are already here
—The aliens are so advanced we can't even understand that they're already here
—"Life is common, intelligence vanishingly rare."
—Our part of the universe is boring
—The aliens think we're boring
—All the aliens have had their own Singularities and live in other dimensions now
Then there's the somewhat noble possiblity that we really are the chosen ones, the first intelligent species, as well as the depressing probability that we, like every galactic civilization before us, will kill ourselves before we can explore the stars.