I personally still don't believe the rumors. Not until it's confirmed. But if MS does do always on, I don't see how that's going to sell well. Not everyone can afford internet. I have several friends that play xbox and ps3 with no internet connection. They come to my house to do updates. There's no way they would buy an always on box. And I'm sure there are more people like them.
Hell, even I wouldn't get the nextbox if it's always on. Sony and Nintendo are the only two companies I will be supporting this gen if this rumor turns out to be true. If they don't think they will lose customers, they need to start reading forums and look at what gamers are saying about it. The idea of always on is universally hated with the exception of few.