I think if the cable industry had a platform for developers to make apps (like on iphone/android etc), the cable software could have been much better. Look at time-warner/comcast/at&t interface - they all suck so much yet there is no one to tell them the first thing about good design or functionality.

I think it is inevitable that this would change in the next few years (with entrants like apple or google in cable business) and you would have all the functionality of netflix on cable. This would be the end of dvds altogether and netflix would die as a business model just like blockbuster is dying today and video tapes died back in time.