I just finished reading Eliezer's April Fools Day post, where he illustrated how good society could be. A future society filled with rational people, that is structured the way Eliezer describes, and continues with linear progression in technology would be pretty amazing. What is it that the intelligence explosion would provide of value that this society wouldn't?
Put differently, diff(intelligenceExplosion, dath ilan).
There are two main differences I can see.
First, superintelligence can create a better utopia. After astronomical amounts of time, dath ilan may have the technology necessary, but I suspect that they would lack the understanding of their own utility function that FAI would have. They are also not immune to politics, and will act suboptimally because of that.
Second, there's a not insignificant chance of dath ilan being wiped out by some kind of existential risk before they're advanced enough to prevent it.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.