A while ago I wrote briefly on why the Singularity might not be near and my estimates badly off. I saw it linked the other day, and realized that pessimism seemed to be trendy lately, which meant I ought to work on why one might be optimistic instead: http://www.gwern.net/Mistakes#counter-point
(Summary: long-sought AI goals have been recently achieved, global economic growth & political stability continues, and some resource crunches have turned into surpluses - all contrary to long-standing pessimistic forecasts.)
I'm not sure really. The conjectured limits in some cases are strong. Computational complexity is unfortunately an area where we have a vast difference between what we suspect and what we can prove. And the point about improvements in constant factors is very well taken- it is an area that's often underappreciated.
But at the same time, these are reasons to suspect that improvements will exist. Carl's comment was about improvement "surely" occurring which seems like a much stronger claim. Moreover, in this context, while hardware improvements are likely to happen, they aren't relevant to the claim in question which is about software. But overall, this may be a language issue, and I may simply be interpreting "surely" as a stronger statement than it is intended.
Given the sheer economic value of improvements, is there any reason at all to expect optimization/research to just stop, short of a global disaster? (And even then, depending on the disaster...)