There is not enough activity to sustain niche communities.

And he discredits his own argument 20 minutes later.

This is still based on fit, evolution, and technology in the context of Earth and humans. Who knows how (or if) evolution could or would work on other planets. Who knows which traits fit would select for, and what process that selection would be based on.

Also, who knows how else technology could look. We have tech that HUMANS couldn’t imagine just 100 years ago. How are we supposed to imagine what technology would look like on alien planets.

My point is: you shouldn’t look at the probability of human technological intelligence. And we naturally can’t look at non-human technology since we haven’t found any. We can’t know the probability. All we know is that it has happened at least once.

He spent 25 minutes contradicting himself and concluded “we don’t know”.

How do you plan on that happening?