Yup that's what I think, I think MS is going to back out of propietary, fixed function consoles and simply make their own mini-PC next time, like a SteamBox, but it will run Windows of course and it will be tailored to compete against Steambox. 

Will be digital-only/centric like Steam is. "XBox" will simply be the branding for the device, and it will have a subsidized price closer to cost so it can under cut Steambox prices. It will have tons of games and all developer support from day 1 because it runs Windows already, so every PC game ever made will be able to run on it. MS will sell these games through their XBox Live storefront. 

And I think this will be out by 2018. It was always kind of the inevitable destiny of the XBox brand anyway I think. 

Completely agree.

the one is already close to "a pc in box" system.
so sure, this is how it will pan out

Soundwave, I don't always agree with you, but this is not one of those times. I do agree that MSoft will quit making consoles to make gaming PCs, but I won't go as far as you and say when it will happen.

Also, because they will be PCs, I wouldn't be surprised if they launch a new model every one or two years.

Where is the difference to what they're doing now? X1 is nothing other than a PC with a custom UI. You can already do everything with an X1 that anyone who wants a box under the TV would want to do with it.
If people wanted a full fledged PC that they can use from their couch they would just use their PC from the couch.

Obviously.

There won't be a new XBox next gen.

Two words why this will NOT happen: Xbox Live.

True enough, but it would be a talking point. If it ran on windows and you could just click on an app to play games it may draw enough attention due to it's name (Xbox) to get people who want a gaming pc but don't want to have to hassle of trying to figure out the components to build one to jump on board. 

With the right marketing (another thing steambox and things like it don't have) it may build interest.

It will be Steam but called Xbox Live and you can access it from any device