From your links ... Kinect has a 1.92 tie-ratio without Kinect Adventures (which is bundled) and the Wii U has a 1.42 Tie ratio without Nintendoland (also bundled)

When you look at the sales of Kinect software what you will notice is that sales of Kinect software roughly match sales of Kinect Hardware, which means that people are picking up software to play on Kinect having never played Kinect before. If there was sustained interest in Kinect you should see software sales trending higher over time. For example:

The 3DS has sold (roughly) 3.5 units of software for every unit of hardware they sold in 2012
The PS-Vita has sold (roughly)  4 units of software for every unit of hardware they sold in 2012
The PS3 has sold (roughly)  12 units of software for every unit of hardware they sold in 2012
The XBox 360 has sold (roughly)  14 units of software for every unit of hardware they sold in 2012
The Wii has sold (roughly)  15 units of software for every unit of hardware they sold in 2012

If there was sustained interest in Kinect you would expect to see the 16 million people who owned Kinect at the end of 2011 buying games for Kinect in 2012; and I don't see much evidence of significant software sales to existing Kinect owners in 2012.

Kinect sensors sold in 2012 according to VGC: 3,342,957
Kinect Software sold in 2012 according to VGC: 11,908,375 (not counting Kinec Adventures here!)

And this does not include digital titles like Wreckateer or Fruit Ninja Kinect, which alone sold about 2 million I think. Of course it does not include "Better with Kinect titles" either.

Anyway, VGC is not a reliable source when it comes to Kinect. MS reported 20 million shipped 6 weeks ago and VGC still has it at 19 million.

If you assume that everyone who bought a Kinect Sensor bought another Kinect game (a relatively fair assumption), that would mean that there was an average of (roughly) 0.5 games sold to owned Kinect Sensor in 2012. With how people's purchasing habits tend to be distributed, that you will have some households buying 2 or more games in 2012, I would be surprised if 1/3 of existing Kinect owners bought a game for Kinect in 2012.

Kinect may be a worthwhile add-on to pursue, but it would be foolish of Microsoft to make it the central piece of their next generation strategy.

Edit: To be entirely fair, I also think it would have been a mistake for Nintendo to release a system where an "advanced Wiimote" was the central piece of their strategy. People know what it is, already have formed solid opinions about it, and interest in it has fallen and it is unlikely to significantly increase excitement about the system.

"assumptions is the mother of all fuck-ups."
That was a signature here.

And who cares if existing Kinect owners or new kinect owners buy a game. End the end of the day it comes down to software sales.

Well, if it really is $499 and and they are focusing on Kinect 2, then I can see Sony have a really good shot with a $399-$449 PS4, that may or may not come with the new DS/Move controller. And given MS's track record of barely supporting core games after the first Kinect came out (one or two games a year), as opposed to Sony's approach of Move being more of an optional controller for some games, I think they have an even better shot. I'm also kind of curious to know if the "new controller" means that MS might completely redesign their controller. Hope not.

It matters because it demonstrates whether there is sustained interest after owning Kinect ...

If the majority of Kinect owners are not interested in Kinect to purchase games for it, what makes you think they will purchase an expensive system to buy games for it?

Compare XBox Live enabled game sales to Kinect game sales, what do you think will provide a better return on investment improving XBox Live or improving Kinect? Compare Kinect game sales to graphically impressive game sales, which do you think would result in higher system sales bundling Kinect or releasing more powerful hardware?

From all of the rumors they are trying to do both.

But I don't really think you can do both and become successful ...

Basically, to duplicate the high performance strategy Microsoft would (probably) have to sell their system for $450 or $500, and to bundle Kinect 2 would result in $100 or $150 added to that. I could be wrong but I suspect the "XBox 720" would do far worse at $600 than the PS3 did, in a large part because of the difference in popularity of the XBox 360 compared to the PS2.

It is very plausible that the NeXbox is 399 without kinect.  Plus the subscription model will let them slide with a high price point.  But yes if it was $600 then it would not sell well.  499 is as high as they can push it and that should be fine.  Im not a fan of kinect personally but it is great for the casual market and they know the casual market is big so they want kinect to ship with every xbox.  they want the hardcore and casual market.  MSFT wants to own the world didn't you know ;P

I'm guessing they will certainly make a cheaper version, and won't mind loses on it just to stay lower priced than the PS4 and get the price conscious consumers.