I bought an HP Touchpad in the $99 fire sale and I still have it. The UX was so far ahead of its time that I was blown away by it. It’s still chugging along without hiccups. I miss the days of such lovely and unique devices.
On the desktop world, the UI is a component of the OS, and is responsible of the whole OS experience.
Hence why the successful OSes that happen to have UNIX internals, those internals are not exposed to the users, and are not optional for most development scenarios.
Hence why GNU/Linux on the desktop failed, while Linux kernel on the mobile and TVs with prescribed user and developer experience has succeed.
Yes as the Server Core configuration it can, but you don't get to replace Win32 puzzle piece that goes on top with something else, you might augment it with alternative UI frameworks, but ultimately it is Win32 at the bottom layer.
Just like on macOS, while UNIX on the bottom layer, you don't get to plug something else instead of WindowServer and related low level APIs. Even with XQuartz, it builds on top of it, just like they build on top of Win32 on Windows.
Compared with the fragmented way of UI/UX on traditional UNIX clones with special snowflakes on top of Xlib and whatever is the sound stack of the month, with exception of NeWS/NeXTSTEP/OS X, they suck less.
It's discussing and product, and that's all the customer actually cares about. When tech news outlets discuss Google Android versus MIUI versus OneUI versus iOS versus iPadOS, they don't care about the way the kernel implements multithreading or what interrupt mechanisms the USB drivers use.
Given its similarity, webOS and Android could be considered the same OS if you're looking at it from an OS designer point of view, but that's meaningless to the readers of this article.
What it can connect to and what protocols it supports all depends on the software you run on it. As long as there is supports for basic I/O, you can run a modern copy of Chrome on it. That's why Android 7 and Windows XP can still be used for day-to-day browsing just fine, even though the OS itself stopped being supported and maintained years ago.