You don’t need to agree with premise 3 to think that working on MCE is a cost-effective way to reduce s-risks.
Yeah, I agree.
For one thing, if we just cut premise 3 in my statement of that argument, all that the conclusion would automatically lose is the claim of “urgency”, not the claim of “importance”. And it may sometimes be best to work on very important things even if they’re not urgent. (For this reason, and because my key focus was really on Premise 4, I’d actually considered leaving Premise 3 out of my comment.)
For another thing, which I think is your focus, it seems conceivable that MCE could be urgent even if value lock-in was pretty much guaranteed not to happen anytime soon. That said, I don’t think I’ve heard an alternative argument for MCE being urgent that I’ve understood and been convinced by. Tomorrow, with more sleep under my belt, I plan to have another crack at properly thinking through the dialogue you provide (including trying to think about what it would actually mean for the graph of future moral progress to be like a sine wave, and what could cause that to occur indefinitely).
(commented in wrong place, sorry)