I find myself mentally blocked when asked to pay a one-off fee for digital goods like music, ebooks and movie downloads, especially when they come wrapped up in DRM. I fear that they might disappear at any moment and I might be forced to buy them again at some later date, which is something I definitely do not want to do. At the same time, I find I am attracted to the idea of a flat fee all-you-like subscription service for the exact same goods.
While I won't pay iTunes several dollars for every locked-up, tightly-guarded movie I want to watch, I might be convinced to pay $15 per month for unlimited access to all music, movies and TV in the store, even if I don't get to keep any of it afterwards. I wouldn't feel so much like I've been ripped off if I didn't pay specifically for any one item and then later had to cancel my subscription. I would feel the same way about books. Rather than paying Amazon $10 per ebook, I'd pay $10 per month for unlimited access to the library, even if it goes away when I stop paying. As long as those titles are still around, and I can still re-subscribe later (perhaps to another provider) I'd be happy.
My point is that an unlimited flat fee subscription model is a different - and sometimes more appealing - value proposition than pay-per-download for copy-controlled content. If you're going to wrap your content in DRM, it makes more sense to ask people to pay an entry fee, not "buy" things that, technically, they won't own.
Mokalus of Borg
PS - My prices are probably much lower than those companies would like.
PPS - But that will always be the case.