The "test case" of DRM-free stuff that I'm most familiar with is Baen Books, who are selling DRM-free e-book versions of (almost) all their titles and -- according to themselves and their authors who are also have books published by other publishers -- "[earn] more income as a publisher and [pay their] authors more in the way of royalty payments from [their e-book line] than any other outlet for electronic books." Based on this, it seems likely to me that the EMI/iTunes experiment is going to deliver on its promise of making more money for EMI.

http://preview.baens-universe.com/articles/auged http://preview.baens-universe.com/articles/salvos6

Of course, it's a different medium, and Baen has also managed to create a community of users who like the company, not just its products. I don't see EMI replicating that, DRM-free music or no, which limits the applicability of the example. (The Baen people love telling the story of their users saying, "you should charge more for this." They created a premium version where you pay more to read an advance copy of the book before the official release date, and they're making money from that, too.)