I think I have more KDE code on my computer than GNU code. Both are undeniably useful, but no one is insisting on calling it KDE/Linux.
Linux is still useful without KDE, but the functionality provided by GNU is critical and would require a large effort to replace.
This isn't really true. You could just grab your userspace from a BSD, or Plan9Port. Clang and LLVM do well enough to replace GCC on most important architectures.
25 years later. Very few works are relevant for that long.
You could also form stacks, like KDE/GNU/Linux, or go all the way and just draw a directed graph of the major software dependencies. This isn't a serious proposal, but I would be kind of pleased if someone actually did this.
However since GNU software is the foundation on which most of the system is built you can argue that it has a much greater importance.
"Measuring software productivity by lines of code is like measuring progress on an airplane by how much it weighs"
Now compare that to how many people have none of the GNU software on their systems.
It's really difficult to determine the relative importance of one software project at this level over another they reliant on each other. The Linux kernel needs GNU as much as GNU needs the kernel (at the moment anyway). You can run the OS without KDE (hence not calling it KDE/Linux).
I can see Stallman's point as he set out to create an operating system called GNU, created almost all of the parts required which were then used by someone else to create a Kernel which was then packaged up with a different name.
Personally I think you can call GNU/Linux whatever you want as the licence its released under has nothing in there saying you need to give mention to GNU in the name. If you package it up you can call it Fred for all I care and I will refer to it as Fred.