I look at Google TV as sitting on top of your existing content -- be it cable or satellite. Then, add apps which like youtube will stream content. So think of it as an addition to what you are already getting -- not replacing it.
Imagine using google search on your TV instead of a TV guide to find out whats coming up...
ie, search for NFL and having it show all the NFL related content in the next hour or two... but actually useful as opposed the search your current box or provider supports now.
Samsung TV's already have a myriad of Apps... my TV can do facebook, youtube, Twitter etc... but Google TV adds more then just apps.
At least, that's how I feel. Good question to ask over at the GTV Forums though