I’m not sure if extinction is a problem either. No one’s left to care about the issues, then.

How long would the currently 17 people in space survive if every human on planet earth was eradicated?

Dunno. I imagine they’d follow soon, though.

It seems to me that the most viable routes to human extinction are through superscaled versions of contemporary disasters: war, disease, and famine.

Although war, disease and famine may kill many people, they are extraordinarily unlikely to cause extinction per se. The human species has so many individuals that only very special risks are capable of reducing 8 billion to zero.

For most mammalian species if they have a stable 100k individuals then they are doing pretty well. So we have 80000x more humans than what would be considered a healthy population in other species.

The risks of human extinction tend to be more long-tail events that have a planet wide effect. For example, a large impact, supervolcano eruption, or engineered bio weapon. AI certainly deserves its place on that list.