I never said it did- if anything, you just equated them in that last post. I think I in fact went to lengths to point otherwise.
Radiohead is mainstream because it's played all the ****ing time. If everybody and their dog have heard of the band and know at least one of their songs, they're mainstream as it gets. If their music is played on corporate radio stations regularly, it's really mainstream. What, exactly, are you looking for here? A total monopoly on all music played in any format, anywhere, ever? Would that make it mainstream? Or maybe we need to carve the image of their latest CD cover into the moon for them to be mainstream- would that cut it, or would they still be one of those underground subculture bands?
Bands like Radiohead develop a good chunk of their fanbase from the pretence that they're somehow a niche, a tiny subcategory of elites who find all the music nobody else will listen to. It's the same basic concept as all those designer brands that charge twice as much for a crappy T-shirt that's supposed to express your "individuality", that everyone you know ends up buying anyway. Same as that "Army of one" bull****- it doesn't have to have anything to do with reality, it doesn't even need to make sense all the time, because people want to believe the myth. Tell someone they're a special snowflake, and they'll buy anything, doesn't matter what it is. The fact that Radiohead fans still invariably claim that they're some sort of oppressed minority (and defend such violently- you should see the flames I've gotten for almost exactly the above paragraph) when the band has to be at the very least in the top 50 sellers right now really just says it all- do you really wanna buy into that kind of horse****? Value the music for itself, not for some meaning a guy who gets paid to lie to people attaches to it. If you still like it then, sans all the advertisement crap, then fine, you like it for the right reasons. I doubt most people would.