If they are out there we should be able to see their technological prowess; harnessing their stars' energy etc. Of course the universe is such a vast place it would be certainly possible to have overlooked or just not seen them at all.
I think about it in a different way: Think about a mayfly. When it is born, the fact of its universe is what exists that day. Let's say, in this case, it's a porch light. To that mayfly, the porch light is a constant in the universe. Not only that, but if you were to go back generation after generation (only days to us) then it would have always been there, since the beginning. Like us, they could make stories about that light and how it came to be, but they would never really understand it. And were they to ever understand it, what's to say they would continue to 10, 100, 1000 generations later. I like to think that they're just out there, and we're just staring at them, not knowing what they really are.