Most analysis following the leaked word that Apple might enter the Internet radio industry focused on what a move would mean for Pandora and all its established Net radio competition. One stock analyst, Jeremy Bowman, writing for The Motley Fool, examines the issue from Apple's (and its stockholders') point of view, and concludes that such a move wouldn't likely be good for Apple.
First, he reasons, it's an ad-supported game, something Apple's not done much of (especially in local markets, where the company would have to build sales staffs... in which Pandora has a head-start). And there's the fact that while Pandora and Spotify are (near-)household names, neither is profitable, due mostly to the high cost of licensing music. And Bowman doesn't think Apple would stand to get any better of a royalty deal than the others, as the labels want competition, not an Apple-dominated space (like in download sales).
Spotify and Pandora users have spent hours and days (even years) perfecting their listening profiles (to a point they'd be pretty unwilling to walk away from those sunk costs to start fresh on another service).
Anyway, reasons Bowman, Apple's strength is its hardware, not "mere pennies" services like Internet radio.
Read his article here.