Our species is at the most interesting point (now + coming few generations) in its evolution I'd think (creation of WMDs, genetic engineering, effecting plant-s

Our species is at the most interesting point (now + coming few generations) in its evolution I'd think (creation of WMDs, genetic engineering, effecting plant-scale changes, artificial intelligence/life, spacefaring, etc.) - a tipping point that makes us most "interesting" at the moment -- so if there's a civilization that's been around for millions (if not billions) of years, I'd expect that they are here now, and that they are in a form (tiny, distributed, etc.) that isn't recognizable to us unless they decided to manifest in a specific form. I'd wager that if we are not the lone civ in the galaxy, that this is probably the case.