This article is a very LLVM-centric view, and it does ignore the GNU idea of a target triple, which is essentially $(uname -a)-vendor-$(uname -s), with vendor determined (so far as I can tell) entirely from uname -s, the system name undergoing some amount of butchering, and version numbers sometimes being included and sometimes not, and Linux getting a LIBC tacked on.

But that doesn't mean the article should be ignored in its entirety. LLVM's target triple parsing is more relevant for several projects (especially given that the GNU target triple scheme doesn't include native Windows, which is one of the most common targets in practice!). Part of the problem is that for many people "what is a target triple" is actually a lead-in to the question "what are the valid targets?", and trying to read config.guess is not a good vehicle to discover the answer. config.guess isn't also a good way to find about target triples for systems that aren't designed to run general-purpose computing, like if you're trying to compile for a GPU architecture, or even a weird x86 context like UEFI.

The GNU scheme does in fact have support for various windows targets. It's just that the GNU compilers don't support them all.

There's MinGW.