“GNU” was always crappy branding. Nobody wants to read it or say it or explain it. “Linux” sounds cool. So everyone calls the whole system “Linux”.
Why isn't it GNU/Linux/SystemD/Mesa/Xorg? Basically every Linux desktop could be described that way.
Heck, if Earth didn’t exist, Linux wouldn’t have happened, so Linux/Earth/Sun/Biology/Torvalds/Stallman/SystemD/Mesa/PulseAudio/Wayland…
GNU nowadays is a tiny part of the desktop. There’s also projects slowly moving to rewrite it in Rust and a more permissive license, other parts are losing importance like GCC losing to Clang, so its relevance is dying over time. Just like the FSF.