One of you touched on it earlier in the thread when they mentioned "Fair Use" and that's what this is really all about - eliminating it.
Hollywood has never gotten over the beta-max decision and has been steadily trying to get it effectively nullified ever since.
The past 10 years have been an exciting time for consumers in terms of video electronics but along with it there has been steady pressure and varied attempts to regain and tighten control over content.
The broadcast flag, DRM, HDCP, etc have all been about getting total media control back to those that create it.
Ideally they would have you pay something for everything that entertains you, each and every time you use it.
In exchange for better quality entertainment they want total control. No copying - period - even backups for purchased content. Oh they may not (can't) go so far as to take mediocre (480i) archiving away but you can bet unless there's a major uproar, they'll effectively limit any kind of digital copying (PVR included) that they're not getting a piece of the action on.