And hey, Windows is just DOS with a bit of new code, and wasn't that just a quick copy of CP/M. Really we should expect Windows 8 to have been called Microsoft CP/M 2012, right?
Some of the names you mention are indeed related, but branding and marketing are entirely different beasts, and from a marketing perspective, it may be perfectly logical to give disparate names to tangentially related technologies.
Windows 8 has no code parentage from DOS. Windows NT was as a completely separate OS design. Compatibility and so on for various submodules, sure, but DOS isn't in the parentage. They've had/have POSIX as well as OS/2 subsystems in there too, but NT is its own thing.
And hey, Windows is just DOS with a bit of new code
If you think that the step from a command line to GUI, multitasking OS is anything at all like cramming an 'X' or 'Live' into a bunch of disparate technologies, then I don't know what to tell you.
Edit:
from a marketing perspective, it may be perfectly logical to give disparate names to tangentially related technologies.
Please explain the logic of 'X' and 'Live'. From where I'm sitting, they're just aliases for '1997-2003' and '2005-2010' (numbers purely guessed). It added absolutely nothing of value for anyone, aside from the marketing team.
From my totally unqualified understanding of marketing, it's because it makes people go "oooOOh" and statistically more likely to buy or even notice the product, because they associate it somehow with fast cars and filthy sex. This makes the "random and without value" renames vaguely sensible in a for-profit corporation: it drives the bottom line. But hey what do I know, I'm a nerd and have barely sold a thing my entire life.
Quitting the devil's advocate role and in support of your position, if nerds had their way, the entirety of marketing and design would be annexed in favour of technically aesthetic solutions (functional product names, stable UIs, uniform web designs, ...), but sadly when speaking of the masses, buying choices are simply not driven by rationality. My ideal world will probably never come, at least in this lifetime.
Some of the names you mention are indeed related, but branding and marketing are entirely different beasts, and from a marketing perspective, it may be perfectly logical to give disparate names to tangentially related technologies.