Bob Lefsetz published an article on Friday that powers this admittedly not very far out prediction.

Streaming–powered by iTunes–becomes the preferred choice of music consumption in the US.

We’ll achieve that by 2013.

Why?

1. Streaming music works.  See Spotify and how well they’ve done in Sweden, particularly.
2. Apple and iTunes already have your credit card, for the couple of hundred of million users they have.
3. Consumer preference for Apple which is demonstrated by iPod/iPhone as the preferred music-player hardware.
4. Poor UI elsewhere including Spotify.  I think Spotify is great, but the UI leaves a lot to be desired.  Apple doesn’t have UI problems. Good UI/UX wins.