See that's the thing... music IS a social status now... it's just what our society has become. It's just like owning a Porsche, you see. If some jerk owns a Porsche he often feels like he can look down on the "little people" driving a Ford Taurus or some such domestic. So it is with music listeners. If I listen to complex, deep music like Opeth, apparently I can look down upon the mindless goobers who listen to Green Day and The All-American Rejects.
It has to do, like most status symbols, with stereotypes. If you buy a Gucci bag, you are hip. If you buy a plain handbag, you are white trash. Any socialite can tell you that. TRL was popular for so many years because it showed music that sheep-like teenagers (particularly females) would listen to and latch on to like lampreys on a trout; bands like Korn, N'Sync, Backstreet Boys, Britney Spears, Eminem, etc. MTV still uses this philosophy today by exploiting bullshit such as 50 Cent, The Pussycat Dolls, and the entire Warped Tour.
Smart folk stayed away from this drivel and listened to decent red-blooded God-fearing music like In Flames, at least until they became commercial, and God forbid any hard-working band try to sell some records! Oh no we can't have that. We want our music to be so underground that nobody, including us or the band members themselves, has ever heard of it. We want our music to sound like a druid is being eaten by a werewolf in a forest on the fucking Moon.
But I digress. The basic idea is we don't want the people driving Tauruses to suddenly be able to afford a Porsche, because WE DON'T WANT TO BE ASSOCIATED WITH THEM. People don't actually hate artists for becoming popular unless they have marginalized their music in order to do so; we hate being fans of the same bands as MTV-watching mental dwarves.
Instead of being proud of White Trash Tanya next door for realizing that a Gucci bag will reflect better upon her tastes, we feel that her owning one somehow drags us down into a lower social class. This is simply the way humans are because humans have a pathological and undeniable need to feel better than other people. It's sad, because when a band becomes popular we SHOULD feel happy for them, their hard work paid off and they are getting the recognition they deserve. But NOOOO, Indie Rock Dumbass Tommy from my high school now likes Opeth, so they are no longer cool. I must get into an even more underground band with a name I cannot even pronounce from Eastern Bumfuckistan and then I will be cool!
People are sad. It's the truth.