To me there seems to be a pattern occurring with the Winows platform. If you go back 14 years Microsoft has been releasing operating system test beds without actually discloing it. I may be completely wrong and correct me if I am, but go back to 2000 when MS released Windows ME, that to me seemed to be a test bed for Windows XP, and windows Vista a test bed for Windows 7, so with that being said, this windows blue might be the real deal. Imagine windows 8 as vista - the public are not liking it, some say its not finished ect. As much as they may be wrong (which I think they are) Microsoft probably never intended windows 8 to be its permanent new OS, that might be windows blue. I remember when Windows XP had a service pack 1 update, which brought loads of performance and stability enhances as well as some new features , in other words the current windows 8 may be another Vista or ME, because Vista was never intended to be a permanent OS, neither was ME, so Microsoft may have the basic "structure" of windows phone and windows 8, waited for the public reaction and the bug lists to come through, fix them and there we may have it. Ttwo OS for two devices that will have the same impact as Windows XP and 7, if this makes sense. Because Vista, visually is very similar to windows 7, windows 7 just looks watered down (though it isn't) but aesthetically it looks cleaner. Windows phone 7 may have also been a test OS for 8. Im may be wrong but this is what I see MS's progressing structure to be, because Microsoft, whatever product they release eventually thy have to get right.
Also it makes you wonder why Microsoft launched windows 8 and are still selling it so damn cheaply, ?25 ? ! I reackon they are trying to get as many people on it as possible for the reasons mentioned above.