This discussion is kind of cracking me up, and I don't mean that disrespectfully at all. I was a college radio dj in the late 80's-early 90's, so it's just that I've heard this conversation in one form or another for literally decades now. There's always subgenres, there's always retro-active re-labelling ("punk" used to mean tons of music that it does not refer to anymore), and commercial co-opting of a term. "Alternative" was the catch-all in the mid-to-late 80's for anything that was an alternative to music then played on commercial radio & regular rotation mtv, but then the combination of some of those bands (REM first, later Sonic Youth & Nirvana) moving to mainstream radio & sales and mainstream marketing of the it all in general killed the term for those in-the-know, and Indie took over as a catch-all, before it became attached to specific sub-genres like indie rock or indie pop. Kinda like "punk" - in the mid-to-late seventies "punk" was a very wide-ranging term, at least in the U.S., but now we look back and give different, more specific labels, to many of those bands.
Sorry if I'm not adding much here. Years ago I chose to mostly step away from worrying about labelling - it mattered when I was in my teens & twenties, but it doesn't matter to me at all now if one person's "indie" is another person's "alt" is another person's "punk".
I do feel what someone (j? sorry, don't feel like rereading the whole thread) said about attitude or morality or whatever. There's always the sense that the punks/indies/alts/etc are not "selling out" (regardless of actual sales), and if they're following a trend it's not a conscious decision. After working with bands from punk to jazz to metal to folk, I have to say that I've met maybe two groups total that actually were selling out, though, in the sense of not really being totally sincerely into their music. Some were certainly more interested in selling, period, though, and that sort of interest is generally frowned upon in whatever independent realm it is we're talking about.