Apple Blocks Spotify in the U.S.
wired.com
wired.com
There's nothing mysterious going on here... Spotify just doesn't make any significant money for anyone. It's a big free party that could disrupt proper businesses.
I also don't see how Apple are 'almost inevitably' going to launch a Spotify style service. Where's their evidence for that, outside a large data-centre being built - which could be for any number of purposes.
Regarding what musicians earn, the most interesting note is probably that the Swedish collection agency (STIM) said about half a year ago or more that Spotify is the number one digital earner for music in Sweden (passing iTunes for example).
As for the bandwidth, see the paper I linked in another comment for some interesting statistics on how much bandwidth is actually needed (tl;dr version, surprisingly little thanks to p2p and caches).
Also, one should remember that, AFAIK, the initial idea was the free account type and Premium came later. It is all about competing with piracy, making something that is easier and more convenient for the user while still giving a revenue stream to the rightsholders.
As for smaller artists, compare it with the situation in commercial radio. A few radio-plays will not get you very much money, but the number of people that listened to your song is actually quite high.
Also, another thing about the ads is sometimes they're hardly ads at all, they're just Spotify announcements. I can't believe they'd be wasting spots like that if they were really pulling in serious advertising money.
spotify has talked a big game, but their "imminent" US launch has yet to happen...and i'm not convinced it ever will.
all said, i'd love to see daniel ek (spotify ceo) & steve jobs at the same table...