Online games that require validating with a central server after being downloaded? Try not to get a virus downloading a crack after the company goes under.
If we consider anything that works to prevent media from being copied in violation of copyright, then there is one solution that does not have a central service, and is not rent-based: watermarking.
Every purchase is watermarked for the specific customer. If they give someone else a copy, it is detectable from who they received it, so legal action is possible. But fair use is never prevented, as copying is always technically possible.
(Yes, it is possible to remove watermarks, but it is also possible to get around DRM - all of these schemes are continuously escalating arms races.)
http://www.defectivebydesign.org/what_is_drm_digital_restric...
If you want to talk about the death of ownership and the rise of rental, and how that might be damaging, that's a fine an interesting topic, but I don't see how it's about ethics.