Except the Kinect sold incredibly well for an expensive peripheral. 24 million units is a bit less than 1/3rd of the total Xbox 360 install base.
Wii sold millions too. Doesn't mean waggle is the next coming of Jesus.
Wii and Kinect were just a "I have the latest cute iPhone, do you?" type mainstream fad. It's marketed to the same kind of people who think talking diabetes meters and tire pressure gauges are just sooooo cool. "oh wow it talks to me!".
Fads die and the mainstream moves on to the next one. Nintendo learned this with Wii U and the inability to carry the Wiis momentum. Remains to be seen if Microsoft will experience the same fate when people get bored of Fruit Ninja and move on to Temple Run 9 on their iPhone 12.
Waggle and arm flailing and shouting at your TV have no place in real games.
And without a 4 way treadmill with a ceiling harness I don't see how VR is ever going to work quite right in the home either.
Things get interesting when you combine a VR headset, a 4 way treadmill with a ceiling anchored harness, and the potential of Kinect 2.0. The closest we will get to a holodeck with current technology.
How about the harness rig being tethered by 4 points with the ability for the rig to tug on the player, eg safety rig keeps the player, upright and centered on the treadmill and also acts as a torso force feedback device. Chaotic multi directional tugs while the screen is flipping around and treadmill knocking your feet out from under you when you crash or get knocked on your ass. You'd be so disoriented and feel like youre falling and off balance, but you'd be perfectly upright and secure from smashing your living room up.
Just a head tracking headset alone does not make VR. It too like 3D will just be a passing fad without everything else to make it work.