orcishgamer: Nothing other than how it's played out so far. The commonality, ironically, has been Amazon.com in each case. With music they forced iTunes by launching a DRM free service of which Apple was actually afraid. With eBooks publishers perceive they are losing their power to direct the market to Amazon, partly due to Amazon's ability to lock in the market to their devices and DRM, so the publishers are the ones pushing the issue in this case.
Eh ... sort of. The move towards DRM-free music had more to do with Apple's dominance. Apple negotiated selling DRM-free music with the labels before Amazon launched its service - which came as a surprise to everyone because if I remember right Amazon didn't negotiate switching their music to DRM-free with the labels (which labels were not happy about). What Amazon did force Apple to do was sell the DRM-free music at that same price as the DRM music where previously Apple's price for DRM-free music was 30 cents higher. It also sped up Apple's negotiations with the remaining labels to sell the remaining music DRM-free.
Renting is still a legitimate method to experience the content, not all rentals involve DRM, either, rented DVDs from Netflix or Redbox, for example, can easily be ripped and shared around. Likewise, double clicking a torrent is still probably easier, yet those services still profit (even if Netflix becomes a worse deal every year).
It doesn't matter what people end up preferring, I'm only pointing out that DRM is in no way necessary to ensure profit in the media industry.
While I completely agree with the last statement, keep in mind that with physical media one has to go out of one's way to rip the content on the DVD/CD/book. With purely digital media, to behave more like physical media, one needs a DRM solution to inactivate a copy after the rental period has expired. A customer could still go out of their way to rip out the media content anyway just like they can with physical media, but again I see DRM for rentals and resale as ensuring the equivalency of digital and physical media when ownership expires or changes hands. Again, I don't believe DRM-free is needed to ensure profits, but there is a philosophical/technical difference between DRM on physical and digital media.
Also I don't have Netflix, but in fairness to them much of the reason their deal becomes worse every year has more to do with content partners wanting more money as they see Netflix get bigger and Netflix not yet being quite big enough to have the negotiating power of an Apple or Amazon.