I know it's "opinion", BUT...
As the saying goes, "Opinions are like @$$h0l3s - everybody has one and they all stink."
So here's mine: most opinions are based on ignorance, and in this article SJVN proves that point. [*]
Claim: "... GNOME, KDE Plasma, Cinnamon, MATE, and on and on. They're all too likely to be as forgotten as the first three Unix interfaces I named. Why? The same reasons you don't know a thing about the Unix desktops."
No. They'll be forgotten BECAUSE THAT IS THE WHOLE BLOODY POINT! The purpose of a desktop is to facilitate user interaction and stay out of the way while doing so. A successful desktop makes you forget it's there. You pick the one you like and then you get on with your work without the desktop asserting itself or annoying the user by flouting its own corporate identity. (Yes, I'm looking at you, Windows.)
The reason why Unix desktops are being forgotten, on the other hand, is that they deserved it. They were, by and large, ugly, primitive and clunky, usually having been added as an afterthought with far too little development and GUI design having gone into them. Even in the mid-1990s most of them looked worse than DR GEM did ten years earlier.
Claim: "Unix died because of endless incompatibilities between versions."
No. Unix died because it was proprietary, because of astronomic license fees and because of ridiculous EULAs, whereas Linux did the same job for a fraction of the cost (or no cost at all to speak of) and didn't try to browbeat the user with an army of corporate lawyers. Unix was a proprietary OS for proprietary hardware that came with proprietary pricing. I've worked with various unixen on ancient NCR mini's, Sun Sparc, IBM RS/6000, a bunch of VME-bus development systems and an industrial controller or two, but it was always unix. The biggest annoyance was that BSD-derivatives had different command line switches than SVR4 offshoots for certain commands (eg. 'ps -ef' vs 'ps -aux') and shell scripts based on whatever shell they ran in, but that was it. What was universal was the cost of it and the proprietary hardware-bound nature of the beast. Linux solved all that because it didn't live in the white-knuckled grip of a proprietary hardware vendor.
Claim: "With the desktop, though, we saw, and still see, endless incompatibilities."
No. The real problem is still (and always has been) applications. If you need to run a major industry-standard application suite (take your pick) your chances are it will only be available for Windows, and if you're lucky for MacOS, but not for Linux. And even for simpler, standard office work the problem is still the same. I have always hated MS Word since it pushed the straightforward, sensibly designed Word Perfect for DOS out of the market, but I have to be honest here: I struggle even more with LibreOffice write at times. And I know I'm not the only one.
Claim: "Mint's leaders don't like Snap because its parent company, Canonical, has too much control over the Snap store..."
This one is actually partially true, but the real issue with Snap (and the reason why its absence on Mint is considered a Good Thing) is that Snap sucks harder than a black hole. It's unwieldy, it brutally forces sandboxing upon the user to a point where a Snap application can't access the files it's supposed to work with, it kills performance, it gobbles resources and is a huge PITA. Yes, on servers there are cases where its advantages outweigh the disadvantages, but not on the average desktop. On the other end of the spectrum, AppImage apps typically have to be installed and maintained by hand, which is a no-no for the average user.
Claim: "As Microsoft moves ever closer to a cloud-based computer approach, Linux may be the last "true" desktop standing."
No. Even if true, what will it matter to the average computer user? People want a computer that simply enables them to do their work without getting in the way of doing so, and what goes on under the bonnet (local desktop or cloud based or whatever) is not something they could care less about. It's only when things go wrong (e.g. cloud services being unavailable) that they even become aware of the distinction.
What the Linux desktop really needs to challenge Windows starts and ends with the availability of mainstream applications. As long as I keep running into the brick wall that is the unavailability of certain applications on Linux (thus forcing me to run them on Windows) we'll never see the year when Linux took the desktop market away from Windows.
[*] Disclaimer: see the first line of this comment...