So in your view the entirety of the 99 cent charge should go to Apple? The song you wanted to download just popped into existence before hand with no time, effort or talent from an artist at all (or discovery by a label)? Please tell me more about this magical music tree.
Well, from my perspective as a consumer, yes, it's a convenience charge. I would be happier if some of it went to the artist. I don't actually know how much of it does.
I'm not sure it's possible to actually curate a comprehensive MP3 catalog without active cooperation from the musicians, at some level. But, if the Pirate Bay surprised me and made a fast way to search and download music that was as easy as iTunes or Amazon MP3, and they had a library of songs that was at least as comprehensive as the for-pay versions, then I might decide that the hassle of keeping my billing info up to date in the other databases was more trouble than changing to the Pirate App. I'm not sure. The actual 99cent charge is so close to free that it doesn't factor into my decision.
But that's theoretical. Right now, the musicians get a few cents, Apple and Amazon get legitimacy and a little bit more of my money.
My few cents per mp3 doesn't add up to much. When I actually want to support an artist, I use Kickstarter, or I buy some merch, or click a donate button.