The argument the great filter is ahead of us though is based on the observation that even with slower then light spacetravel, over the timeframes of the existing universe a species could still colonize the entire Milky Way in something like a 100,000 years with von Neumann probes (of which organic life would be a good basis for building one).

There should be life everywhere it's possible by technological panspermia - but we don't seem to observe that. What stops elder civilizations from doing this, is the big mystery.

Unless of course, as a poster above notes, if we fire up the JWST and discover chlorophyll-fringes in the spectra of just about every rocky planet we can see. That'd imply a lot.