It appears that SETI capability depends on both the passive and active communicants having either advanced signaling gear (radio, lasers, etc) or space travel capability. Is it possible that ETI's technology may have evolved in a totally different direction? Just because we have developed promising SETI-applicable science doesn't mean everyone, or even anyone, else has. What if the whales evolved engineering based on the resources of their environment, perhaps their own communications acoustics or organic chemistry based on specially bred slave species, instead of mechanics and optics and electromagnetism as we did? Alien cetaceans are not likely to stumble onto fire or E&M, or the wheel but they may be very clever mathematicians and biologists. Just think how different our own technology might have evolved if the materials to make clear glass (for lenses) had not existed, or if earth were constantly shrouded by clouds, or if we were a marine or subterranean species.

Instead of thinking about technology as a stage all intelligence must pass through, perhaps we should think of it as a huge tree of possible outcomes and we simply are on the one branch that leads to the stars.