This, I can agree with. But with the games on the way I still think it can be a success. Time will tell. The Xbox 2 however, I think will be a monster.
I don't doubt that if they stick to gaming, their next console will make the mistakes the Bone did. There will be no motion control hype to get in the way of their vision for the next XBox. I do say that they are in a sticky situation over all. Sony is going to want to keep Gen 8 going for a long time (likely, not as long as Gen7, but still).
The biggest unknown ahead for gaming is whether VR will catch on. If it does, expect Sony to go all in with Gen9 and if not, expect Gen 8 to be a somewhat shorter gen because the next leap in tech will be a whole lot clearer (4K gaming). Until ATI and NVidia can get single-chips running cool and capable of 4K 60fps, we're looking at a pretty long gap. This could deteriorate relationships with 3rd party and XBox.
I'd be weary of the long-term trap that Sony sprung if I were management at XBox. Saying that being real as real can be with no fanboyism. If Oculus Rift and Morpheus become commercially successful, it will be harder for MS to justify to consumers the need for upgrading simply for the reason of better hardware. At the same time, the XBone is tangibly under-powered to do VR meaningfully. It takes a lot of horsepower.
VR is going to be very interesting as I'm not sure it will ever truly take off outside of a very niche group. No doubt MS is looking into it, along with utilizing the cloud with their games. I wouldn't be surprised if Oculus Rift ends up on the One at some point. And while I don't think we'll see a Kinect 3, voice commands will be a part of the next Xbox IMHO. It'll be very interesting to see how this all plays out.