I once wrote that one reason iTunes doesn't support a subscription model is for the sake of iPod lock-in: once you've bought a bunch of tracks with Apple's DRM, you can't switch to a non-Apple player without losing that money.
I also wrote that I have continued to buy most of my music from Amazon rather than iTunes because of the low bit-rate of iTunes downloads. I can tell the difference between an iTunes 128kbs download and a CD and it's significant to me.
It looks like the Apple/EMI deal does away with both of those objections to buying from iTunes, at least when I buy EMI tracks. They may now be purchased without DRM and at double the bit-rate -- basically good enough that I have not been able to reliably discern a loss in sound quality. In fact it's the bit-rate I use when ripping CD's.
I still think lock-in was part of Apple's strategy. But since it's turning out that only 3% of the music on iPods comes from the iTunes Music Store, the hoped-for lock-in is just not occurring. Apple will do better by giving users a better experience, and that means getting rid of DRM.
I predict that now that EMI has made the first move, other labels will follow suit, akin to the way other airlines tend to follow when one makes a major change in fares. As long as everyone is doing the same thing, things can go on as they are. But then when one makes the inevitable shift, the others must follow to remain competitive.
But it is not as inevitable in this case as it often is with airline pricing, because music buyers can't just switch over to EMI. They want the albums they want, and those are available only from the labels that make them. The general switch to non-DRM'd downloads may take quite some time. Other labels appear to be betting that they can maintain DRM until CD's go the way of vinyl, at which point, they appear to be assuming, DRM will actually help them rather than merely be a nuisance to consumers. (DRM doesn't help them now because most recordings are still purchased on CD without DRM.) But CD's appear to have a fair number of years left in them, so my prediction is that that's a bad bet.