Maybe the most plausible third options is that we are theoretically not alone in the universe and complex life is abundant, but the universe is so big that there are no way we can contact with any of the intelligent life forms. We're just underestimating the size of the universe.
It's like living on a Pacific island 5000 years ago. There are definitely other people in the world but there is no way you can contact them.
It's like living on a Pacific island 5000 years ago. There are definitely other people in the world but there is no way you can contact them.