This thread is kind of funny - so much mis-use of language, wild speculation based on the vaguest details, and prophecies of doom and gloom as well as glorious futures.
I guess it's what makes forums both the best, and worst, way to get and then discuss news.
My 2 cents:-
The Xbox one is already a locked down PC, as is the PS4. The Xbox one is running Win 10 already - it just hides it.
The choices are:-
1. Do you want complete hardware revisions every 7-10 years, generally throwing out/losing your old games, but in theory getting GFX ahead of the benchmark PC curve due to subsidised hardware at the start of the generation. Plus other benefits of development/gfx for one system.
Don't forget that on the dev side there have to be big lurches too as everyone starts making games for the new console exclusively, both consoles, or just the old console.
2. Do you want incremental revisions every 1-3 years, generally keeping backwards and forwards compatibility, dev is a bit harder but essentially is implementing GFX sliders.
Games will transition in more of a grey/gradual way as the profits from making the game work on the oldest platforms will become less than the profits of making the latest and greatest game for the newest platforms.
There will be lumps and bumps along the way e.g. when Xbox 2017 transitions to 16 gigs of RAM rather than 8 and devs have a real choice whether to use that extra space to make a game "better", or stick with 8 for full compatability, or build in an option for both.
As another view - look at the world of porting - games could launch on the newest 2 or 3 boxes and then have a separate smaller/cheaper team working on a stripped down port for older boxes.
IMHO it's all the same process just sped up. Even 6 or 7 iterations of an Xbox will be a hell of a lot easier to test/dev for than the almost infinite number of PC configurations....
The word "Xbox" means Brand first, Platform second and hardware console third.