The problem with xb1 isn't and never was the Kinect. If you ever used it you would realize that it just isn't. Kinect works. And with a little patience works better than ever. The Kinect as a usp for the xb1 is simply the whipping boy of those who never used for it.
Kinect impact the price and for all the great things it achieves it is in no way critical for the system: it is a gaming system and in most genres and more critically the games that sell the most have no use for it. It comes at a premium and core gamers does not care enough to pay for it.
No need to look further: the value proposal is not here for lot of people.
In reality the problem with xb1 is simply the strength of the GPU and/or the quality of the tools available to developers to make it sing. If the xb1 had an on par gpu so fanboys would not be able to run to digital foundry for validation of their console choice every week and gloat, sales would have stabilized at an acceptable rate and the Kinect would have stayed. If you were getting 1080p on average games at 60fps or even 30 fps on average... Kinect would have stayed.
With If I can put Paris in a bottle, and twice a day. Core gamers mostly do not care, kinect comes at a premium, that fact remains. How that would have changed sales, impossible to tell.
As for the tools well I'm not sure about what went wrong throughout the xb1 maturing but coming with a system running 3 OS, with an API that doesn't present yet all the benefits you usually get on a console is in no way an excuse or something costumers should be bothered with.
Kinect was removed mot because the technology wasn't worthwhile but because of sales pressure on the console. That's really all this is.
The other way around, it was forced into the system which came at a premium, customer showed few interest which translates in lesser sale and pressure on msft shoulder.
Whether technology is good or not is irrelevant if customers are unwilling to buy it.
I don't want Kinect, I now live in a 94 m2 house, yet the living room is not big. The Tv is pretty close from the couch, I won't move either or the low table in between to play games I won't buy... or play only every once in a while. I don't want to speak loud to my xbox either, end of the line. Sorry I've no interest. It seems plenty of people thinks the same.
It is damn simple, it applies to almost everything, I could have bought a car that does this that, etc. I did not as I don't care. it was not worth the money for me.
It works the other way around, I used to be attracted to tablets, after spending some time with a couple of them (including a real nice Ipad mini and a nexus 7) I think I'm never going to buy one, I prefer those new netbook. Lots of people thinks otherwise, I don't think they are fools, mislead, etc.