I feel like Europe would have raves that put any North American city to shame. aOm, you certainly have an interesting taste in music. I don't know much about the history of my favorites, but I know most of them come from NYC. Well, Cleveland too. Kid Cudi, Jay-Z, Ratatat, Peter Bjorn and John, Spoon, Vampire Weekend, Talib Kweli, Matt & Kim, and MSTRKRFT have dominated my playlists lately (if you cared to know).
Regardless: can cities really be judged on how much original music comes out of them, or should they be judged on how their venues, populations, and environments attract established musicians? No artist on tour would think to skip NYC in favor of a less vibrant city, even if said hypothetical city had more "original" artists. Just my opinion.