Every issue related to the existence of aliens must answer that paradox first. My favorite interpretation: we are the most advanced civilization in the galaxy.
"Why would they want to visit us?" - this can have trivial answers: the same reasons why we study ants today.
I like this one the most: "It is the nature of intelligent life to destroy itself"
There could simply be a technological ceiling. Once civilization reaches the ceiling, it hits it's head on the ceiling, and falls down the stairs either destroying itself or at very least losing most the progress.
Every issue related to the existence of aliens must answer that paradox first. My favorite interpretation: we are the most advanced civilization in the galaxy.
"Why would they want to visit us?" - this can have trivial answers: the same reasons why we study ants today.