the core concern of avoiding a human extinction scenario.
That is not the core concern of this site. We are in a human extinction scenario so long as the problem of death remains unsolved. Our interest is in escaping this scenario as quickly as possible. The difference is urgency; we are not trying to avoid a collision, but are trying to escape the burning wreckage.
If we can’t stop dying, we can’t stop extinction. Logically, if everyone dies, and there are a finite number of humans, there will necessarily be a last human who dies.
[edit] To those down-voting me: I take my lumps willingly, but could you at least tell me why you think I’m wrong?