I would like to add that although I do know who the Wombats are I do find myself surprised (not angry) when an act I've never heard of comes to town and sells out the club.
Unfortunately I think it says more about me than the act or their fans, though.
 indeed.  that's rather self-aware of you... i like.
when an unknown band sells out the club, my first thought is "maybe i should check them out".  hit rate is pretty low (hence the maybe), but i'll still give some of them a few minutes on spotify/last.fm/myspace/etc.  ya never know what you'll discover.
your post made me think of a possible explanation for the anger: "i'm a music guy, and i'm into 
good music, therefore any band that i haven't heard of must automatically be 
bad music.  how dare they sell out a club!" 
