Rather then apocaliptyical filter, the most probable reason is that space is so wast that even if advanced life was common, chance of meeting/observing one would be next to 0. Think about our civ living on a sand grain in the desert - the chance is almost 0 to encounter another civ living on sand grain on random desert location no matter how advanced your tech is.

yikes - that's true, we could still move life beyond earth and still never meet another civ. I didn't realize this at first but I was conflating the two