A couple of things:
Even for non-negative utilitarians, I think the marginal value of working on reducing extinction risks on its own is much less than is generally currently believed.
One crux is whether we assume that the future is likely to be high-value as it is. A core claim of those who think working on extinction risks is the most important is that we are very likely to have a high-value future. For many reasons, I am skeptical of this claim. While one may argue that we are making progress in including more beings in our moral circles, we’ve arguably still not reached a state where we’ve even reached parity in terms of welfare, particularly if we include non-human animals. To claim the future is very likely to be high-value, particularly to the extent that some anti-X-risk individuals claim, is fairly ungrounded.
As someone who is sympathetic to a form of negative utilitarianism and anti-frustrationism, I think that the lack of creation of value is generally secondary to the reduction or prevention of suffering.
Many very rich and highly influential people are very concerned about extinction risks. Aside from the problematicity of such individuals being an overwhelming source of funding for movements like EA, it would suggest that extinction risks are less neglected than suffering risks. For reference, Animal Advocacy Careers has reported that the global annual level of funding for farmed animal advocacy is <200 million USD.
I only leave 1 unit away from being the most towards valuing futures where we survive because of uncertainty that I might be highly wrong about something, whether it’s my ethical framework or about marginal value of working on extinction risks.
Some caveats:
I find some of the more extreme claims or theories from individuals and groups concerned with S-risks to be implausible, and I personally think pursuing some of these directions is not an effective use of time and resources. Ditto for X-risk claims.
I think there are deeper systemic issues (e.g. current instantiations of capitalism/neoliberalism) which are driving us towards both higher extinction risk and higher levels and expected levels of suffering. This is what I am personally driven towards focusing on, and not coincidentally, I think we need more focus of this sort.
May add more later.
I’m going to press on point 2; I think this is self-defeating as it suggests the future will just be bad, so by this line of reasoning we shouldn’t even try to reduce extinction risks.