Hmmm . . . the old "new disposable" technology vs. the "old iron" argument again . . .
I'm certainly no elder statesman among this bunch by any stretch of the imagination, but I have been racing since the end of the classic lightweight period (about 1984) on and off through the present. At 6'4" and 203 lbs, I am certainly not kind to equipment. I've never owned a set of lightweight aftermarket wheels (excepting those SR/Nisi Solodials w/16 ga. 4 x spokes and Criterium Setas in '84 that didn't last very long) because most don't last the whole season with me anyway.
That said, I can honestly say that at the upper end of componentry (chorus/record/dura-ace) I don't really see a difference in durablity or reliability, including the narrow chains and 9 speed clusters. Bottom brackets, headsets, and cassettes seem to last just as long as they ever did. Yep, those SR hubs were silky smooth, but the rear axles broke like twigs. Are the ergo/STI shifters problematic? No more so than a slipping NR lever or stripped Simplex retrofriction. Yep, those new hollow Dura Ace BBs are wonderfully light--and creaky.
But hey, I still get just as much enjoyment out of friction-shifting my 5sp Gianni Motta as I do cruising through the 18 speeds on my TIG-welded disposa-bikes. I just don't race it . . .
I think it's a wash, but this is my personal experience only--I don't work in a bike shop and get to see what folks bring in to be repaired. I'm sure mountain bikers mow through equipment like inner tubes, but that's a whole different set of factors at work.
Rick Holstein