Going Mainstream

I had been thinking about this idea for about a week then read this article on Flavorwire about bands "selling out." Implicit in the piece, and I think in comments elsewhere (recently on the NPR All Songs Considered Podcast, for example) is the assumption that bands tend to progress toward selling out or going mainstream. It seems we expect bands to become more polished, "radio friendly," "pop" or what have you as they develop as bands. I was thinking, where does this assumption come from? I remember it being a pretty big part of my attitude growing into music fandom. Part of it for me was thinking about when to join with a band and when to jump ship. If a band started out too weird, lo-fi, punk, noisy you might not like them until they developed their sound and matured - a good example here being the Replacements. If they continued getting too mainstream then you would pull out the old "I liked them before they got popular/mainstream/polished/boring" cliche - then you could argue about the point at which the Replacements lost their "edge," typically just before or after Don't Tell A Soul. But it seems that maybe this whole thing is just a product of the punk/post-punk era. Those bands typically got more polished because they got better - at playing their instruments, writing songs, using the studio. More recent bands - I'm thinking of two dominant forces of the past twenty years: Radiohead and Wilco who, if anything, seemed to get weirder, more experimental and less mainstream sounding as they matured (up to a point). For Radiohead the examples being OK Computer into Kid A / Amnesiac and for Wilco Yankee Hotel Foxtrot with its weird radio noises and A Ghost is Born with its 11 minute drone, Krautrock influences and abstract Neil Young guitars. It seems that the Strokes have been kind of assuming this progression as well - the loud, radio and arena friendliness of First Impressions of Earth that resulted in critical rejection of it creating a retreat into the more "Strokesy" sound of Angles. Maybe they didn't realize that Radiohead and Wilco had made it cool to be weird and experimental. Certainly James Murphy's comments about his post LCD plans suggest that he does.