Actually I didn't remember smugness being a huge factor in rock/pop really prior to... well I was going to say Britpop... then backdate it to Baggy/Madchester when I suddenly remembered the white-soul thing of the late-Eighties, as blood-curdling a parade of self-satisfied visages as you could possibly imagine (see above). And let us not forget that veritable Smugzilla, Tony Hadley!
The smugness is probably related to "intelligence"/"sophistication". What connects Curiosity and Foals? It's some strange phrenological hipster-continuum, innit?