What people are discussing is whether there is a specific sound to indie, considering its origins. Think of an indie film. Are they all the same? While there are similarities between all indie films, an indie film also needs a genre, whether it's comedy, romance, horror, or...whatever the name for the genre with art films is. Artsy? But the point is, just like films, there's indie rock, indie punk, indie country, because it has to do with the record label, not the sound for the most part.
OP's post was about the alleged "indie lifestyle" which is in fact a well known concept, contrary to the belief that it
only means a band releases music independently.
It's original meaning was to do with the record label. Now it often isn't, I remember the indie rock hype in the UK back in the mid 2000s, bands like Kasabian, British Sea Power, Arctic Monkeys, Kaiser Chiefs, Franz Ferdinand; they all have a distinct sound. Then over in America you have the indie pop scene consisting of a lot of bands with a similar sound as well. Sure it's broad, but if you think about it almost every genre is.
Indie is a genre; and as for the meaning of releasing music independently, then it's a separate word to simply describe a band. It's like trying to discuss the importance of buying food from the supermarket or growing it yourself. Important to the person that's growing the food, but pretty much irrelevant to everyone else. Why should it matter to the listeners whether a band are signed to a major record label or not? It doesn't affect the type of music a band have at all, so it can't be used to describe them. If someone asks me what my favourite band is, I don't say "oh they're a Factory Records band" because nobody would have a clue what I'm talking about.
This word indie has been thrown around so much it doesn't even have a real, single definition anymore.