^ And I meant to say the rotating door of studio artists. It's what my uncle who lives in Nashville does -- name a big country act in the last decade and odds are he's done studio work for them. He explained to me what I suspected a few years ago:
You have one band or act that is a progenitor, and in the event they become highly palatable to mainstream audiences in an organic way and blow up, every major label scrambles to "discover" the next similar act to cash in. Looks matter first. Welch's look completely embodies the British alt chick rock explosion that's happening ATM. They're talented enough to make somebody into something they're not in the studio, then the tour happens, everybody realizes they're not all that great, then it's on to the next fad.
I guarantee that anybody with a halfway decent voice and/or some basic vocal training can be sat down in a studio by Sony BMG or Universal Music, etc. and produce an album as good as most stuff out there. It's the visual appeal most people lack.
Whole thing sucks because it ends up devaluing the work of aforementioned progenitor, because it makes it nearly impossible for any truly talented acts to experience sustained, large scale success. So it goes.