No one will EVER contact us, SETI is our special human version of vanity
There are three things basically wrong with our rather primitive scientific 'assumptions'.
1. deterministic processes -as a biological species such as ours- may be extremely unique/RARE in the cosmos. Thus, many different life forms MAY exist, - true?- but it is impossible to detect any similarity between us, (the lowly carbon forms) vs. silica and/or perhaps the &%**F#4^ species. Perhaps we cannot recognize their time scale, this alien physiognomy, their natural laws, or even physical manifestation. If Ray Kurzweil is correct, we become digital and quickly all signals disappear. The time span of - say- 100 years of 'radio waves' broadcasting is minutae on a cosmic time clock.
2. What if (?) Drake's equation is overly optimistic, as in way off, and assumptively factually wrong. No Goldilocks planets, too many estimated optimistic probabilities, too much of a similar 'likeness' equated that does not exist, and too short of an evolutionary timescale which evolves where we (life in general) expose those ubiquitous radio waves to the rest of the universe. Looking "back in time" by distance was just too slow, or, -way too fast in each segment investigated. Ooops, no one IS out there. No one.
3. More of a personal supposition of mine: Technological evolution is so pervasively dangerous that this -conclusively- must end in a rapidly developed inextractible, inescapable extinction law, one that is on a very short timescale. My explanation, we just dream and envision incorrectly: Every species that evolves, eventually evolves on a logarhythmic advancing scale that accelerates the possibility of multiple, massively numerous potential venues of extinction. This possibility is so large, that it is absolutely improbable that anything other than this extinction event MUST occur. Hence all intelligence universe-wide is a brief blip in a nanosecond of the cosmic clocks. Thermodynamic laws have one constant: Everything always changes.
We are looking, they aren't.