I happen to strongly agree that moral discount rate should be 0, but a) it’s still worth acknowledging that as an assumption, and b) I think it’s easy for both sides to equivocate it with risk-based discounting. It seems like you’re de facto doing when you say ‘Under that assumption, the work done is indeed very different in what it accomplishes’ - this is only true if risk-based discounting is also very low. See e.g. Thorstad’s Existential Risk Pessimism and the Time of Perils and Mistakes in the Moral Mathematics of Existential Risk for formalisms of why it might not be—I don’t agree with his dismissal of a time of perils, but I do agree that the presumption that explicitly longtermist work is actually better for the long term than short-to-medium-term focused work is is based on little more than Pascalian handwaving.
I’m confused by your paragraph about insurance. To clarify:
I don’t expect insurance companies to protect against either extinction catastrophes or collapse-of-civilisation catastrophes, since as you say such catastrophes are uninsurable.
I suspect they also don’t protect against medium-damage-to-civilisation catastrophes for much the same reason—I don’t think insurance has the capacity to handle more than very mild civilisational shocks.
I do think government organisations, NGOs and academics have done very important work in the context of reducing risks of civilisation-harming events.
I think that if you assign a high risk of a post-catastrophe civilisation struggling to flourish (as I do), these events look comparably as bad from a long-term perspective as extinction once you also account for their greater likelihood. I suggested a framework for this analysis here and built some tools to implement it described here.
Of course you can disagree about the high risk to flourishing from non-existential catastrophes but that’s going to be a speculative argument about which people might reasonably differ. To my knowledge, no-one’s made the positive case in depth, and the few people who’ve looked seriously into our post-catastrophe prospects seem to be substantially more pessimistic than those who haven’t. See e.g.:
Do you have a sense of what proportion of biomass they made up from 1900-1950?