It's nice being pretty much on the outside of all this

My favorite artist really is Indie, though she's working toward being in the commercial category of everyone the article mentioned. Which Thom Yorke stated is a sinking ship anyway, so maybe it's better for her right now to remain Indie.
Brit is as far as I am invested in this article. She had 3, which did amazing. Sales across the board are on a decline though and while she sells a lot, its not like she used to do during her BOMT and Oops days.
I believe the decline affects new artists more than older artists because the older artists already have the proven track record and fanbase. Any strong releases as time change proves they keep their star power, or lose it, depending on who it is and when it's released. Artists like Taylor Swift and Lady Gaga are proving high numbers are STILL possible, so people ARE buying and simply the decline across the board can't fully be blamed for sudden drops from former power houses. They are two NEWER artists beating the odds too and doing some amazing sales. Eminem will prove the old class still has tons of pull and Drake will show it can still work, yet again as a new artist, in this time of fading music sales.
The bottom line is really quality material from a likable artist. If you create something with quality people will be willing to pay for it, but music is slightly different because you have to be likable too. If they don't like you, you can forget it. They sell their image as much as their music and if they don't match you're not going to sell.