No one actually buys from iTunes!
"Apple /is/ iTunes. It's their bread and butter, their cash cow and their lock-in to keep the customers "loyal" to them."
Actually... no. That's all a big myth. iTunes means almost nothing to Apple.
Apple freely admit that iTunes barely makes any profit, and they also admit that hardly anyone uses it. According to Apple's own boasts, they've sold a billion tunes and 100 million ipods: that's just ten tracks (one album) per iPod over the entire lifetime of iTunes. An average of one album per iPod is hardly a lock-in, is it?
The vast majority of ipod owners use their ipods mainly for DRM-free tracks, either from CD or from more dubious online sources. Very few of them actually buy tracks from iTunes.
The vast majority of Apple profits come from the iPod hardware sales, and if iTunes disappeared completely it would barely affect these profits. The bottom line is: they don't actually care where you get your music, as long as you buy their music player, because that's where almost all their money is made.
There isn't really any profit-related reason for Apple to keep iTunes going, they're mainly doing it for PR.