1) It's not just MS pushing the flat-UI trend. Apple and Google are too, along with every other Web/UI designer out there. Everyone's doing it. MS's version does seem to be the ugliest though, mainly because of the horrible color picks.
2) The users you seem concerned about like this stuff. They're all buying and using Windows, along with Macs, iOS, Android, etc. devices. There's simply no serious effort being put into any UI alternatives. There's some stuff going on in Linux-land that has a minuscule marketshare, but that's about it; even there, the most popular desktop is Gnome3, which is on the same bandwagon in many ways.
I actually don't mind the Windows 10 UI as it happens, but if there were the variety of options for Windows that there are for Linux, I'd certainly see if I could find one I liked more.
Same goes for MacOS, iOS, and Android.
In a sense though, this is what I consider to be the strength of the windows UI. With the tight coupling, you can make guarantees on the UI covering all possible configuration options. At the same time, it allows a fixed standard of how to implement configuration. (Some of this comes from windows being monolithic)
The end result is a 'unified' UI where there are user-friendly ways to configure a system. Most notably, it is a lot easier to 'explore' the configuration options of windows as opposed to any linux distro.
I do have to say, $9.99 is a pretty good price for this. But this again reinforces my point: if people really hated the Win10 UI that much, a $10 purchase should be nothing to fix it.
Also, I only looked over the link cursorily, but does this fix the whole Metro interface? That's my big complaint with Win10; when you're on the regular desktop, it isn't much different from Win7. It's when you want to load a new program, or use the Settings, or stuff like that you suddenly find yourself in the purple hell that is the Metro UI. If this Windowblinds program is only letting you skin the desktop stuff and not changing the whole start menu, then it's not really fixing the problem, just making the crappy, clunky Win7 desktop more pleasant to use.
I don't like the Windows desktop that much (I like the start menu and such, I don't like the look and feel and other things, which is why I'm a KDE fan). But I can deal with it fine; it's the Metro stuff that's really horrible to me.
For whatever it's worth, Windows 10 is one of my favorite looking user interfaces, especially with its dark theme. I am not sure why so many mainstream operating systems do not offer viable dark themes.
Oh, and the whole "spyware" trope is becoming overworn. User analytics is here to stay, and practically every website and browser does it anyway. At least you can disable it in Win 10 if you are so inclined. Me - I would gladly give Microsoft my data to they can prioritize features for windows 10.
Where is that option? Also, it's easy to get a browser that doesn't phone home and a plugin that stops websites from doing it.
I think we shouldn't take the defeatist position with respect to surveillance. I know that techies like us can block this kind of traffic at the network edge or chase down the multiple settings it takes to turn this off, but not all users will be this sophisticated.
We should be pushing back against surveillance in how we use our own computers.
User analytics and tracking everywhere (including IRL with for instance face recog in shops), Facebook curious to know if they can manipulate the mood of their users, Google/Microsoft/Amazon investing in "big AI", Money doesn't grow on trees, Do the maths.
You calling things "tropes" or "user analytics" doesn't change anything, and having to use euphemisms tells me deep down inside you know this, too.
Also, no.
Design language is getting an update.