When did Indie go mainstream?

I turned on VH1 the other day, and the number one song on their morning "Countdown" (of the ten videos they decided to play, I guess) was Mumford and Sons "Little Lion Man".  I really dig the song, and this wasn't the first time I'd heard it, but I never thought I'd hear it on VH1 (I guess I never really expect to hear any music on VH1 or MTV, but that's a different matter.)

There was a time when this kind of music would never have had a chance of being "mainstream" and I don't know what exactly has happened in the last decade, but that has changed apparently.  I remember in 2000 when I discovered audiogalaxy, and suddenly was getting into Neutral Milk Hotel, the Magnetic Fields, and Belle and Sebastian.  I remember getting hit by a ton of bricks by In the Aeroplane over the Sea and Transatlanticism.  But mostly, I remember the completely accidental way I discovered Spoon.

My brother sent me a text message the other day, asking me an interesting question: how many bands can you think of that changed singers but kept going on with the same name.  He offered Van Halen, AC/DC, and Black Sabbath as examples.  I was at work, so I had plenty of time to think about this (my job these days is cashiering for a fast food place on campus during the 2:00 to 6:00 doldrums) and at first it seemed like this would be a fairly rare occurrence.  Very few things are as singular about a band as the singer - most people won't notice when a guitarist leaves a band, or a drummer, even though they may be replaced by someone with a very different style.  But even a very similar singers in style can have very different voices, and for a band to continue simply being recognized after such a change must be difficult.

But as we talked about it, more and more examples kept coming out.  10,000 Maniacs, Pink Floyd, Queen, Alice in Chains, Fleetwood Mac, Black Flag.  Goo Goo Dolls, depending on how you want to look at it.  We didn't even count bands that don't really have a single lead singer (the Beatles, the Band) or where someone else occasionally takes a lead vocal (the Cars, the Stones, the Who).