indie rock has grown in popularity in the usa last years, but in europe and latin america has been big since 2003

Seems like you answered your own question.

Indie rock has been around since the early 80s, and grew out of post-punk and a few other scenes. And has been popular in America since the early 00s with bands like The Strokes. Half-*ssed "indie" bands like Gotye, and Foster the People are no indication of indie's popularity, but it's mainstream popularity. Indie bands have been breaking in the mainstream since 00s. See again The Strokes, Modest Mouse, Interpol and also The Killers, are some bigger examples. Indie has been around for years, with bands like Pavement, My Bloody Valentine, etc. It's where alternative rock came from, Alternative came from indie, alternative and indie were synonymous on the 80s. By the time of the late 80s and early 90s when alternative broke into the mainstream, Nirvana, Smashing Pumpkins, Janes Addiction, and band in that vain were breaking into the mainstream and displaced metal and synthpop.  Music that was commonly associated with the indie scene(shoegaze, grunge, dream pop, madchester) when it broke into the mainstream was called alternative, indie that stayed indie that stayed non-mainstream was still being called indie. Breaking it into two different genres. Alternative became a who different monster by the end of the 90s, but it started fading by the mid. Indie on the other hand evolved in another way. While alternative birthed bands like Korn and Limp Bizkit, Indie had Pavement, Death Cab For Cutie, Modest Mouse(90s modest mouse) Of Montreal and by the 00s, The Strokes, Deerhunter/Atlas Sound, Arcade Fire(who's first album came out in 2003 or 2004). Also indie isn't a genre, it's a blanket term for a few genres of music associated with the indie crowd. And indie is not taking over, it will not become all emcompassing in the mainstream, as I said a few indie bands break into the mainstream every once in awhile. The indie scene is always evolving outside of mainstream radio play, as that what it means 'independent', and is always evolving.