Perhaps because what we are looking for doesn't want to be found. For us, finding intelligent life would be a massive change in our reality and understanding o

Perhaps because what we are looking for doesn't want to be found. For us, finding intelligent life would be a massive change in our reality and understanding of life because right now, the current state of affair is that we're alone. But what if these other beings are used to a universe with billions of civilizations competing for resources of various kind (including biological, innovation, etc). Why draw attention to yourself?