I apologize for failing to follow the logic. It seems that a man holding the directorship of something called the Future of Humanity Institute should be more optimistic about humanity and its future, but this fellow is a downer:
For example, it might be that any sufficiently advanced civilization discovers some technology--perhaps some very powerful weapons technology--that causes its extinction.The Universe abounds with so-called Great Filter events that have utterly nothing to do with the inevitable self-destruction of sentience, fashionable though that assertion may be. Gamma-ray bursting stars, asteroid impacts, ice ages for crissakes, any of which would roll back the calendar on our species if not obliterate it outright.
It isn't a Great Filter, it's thousands of calamities, randomly scattered across space and time, and we haven't been whacked by one yet but we still can be. Only microseconds ago in geologic time have we become aware of the potential for these calamities. It will take real geologic time for us to move a significant number of ourselves sufficiently far away to be spared the greatest of these calamities.
It may be that there are hundreds or even thousands of other spacefaring civilizations out there, dead before they got out of reach of the nearest GRB. For each of them, there are millions of other extinct civilizations buried under kilometers of ice, then ground to silt when the glaciers retreated, through a hundred cycles of glaciation and thaw.
I'd be surprised to find there are more than 3 interstellar races anywhere in the Universe at any one time, but then I haven't done the math.
Arguing that we're doomed for, or safely past, some single inevitable culminating point in the development of sentience is itself a form of observation selection effect.