Yes, and there is Linux without GNU, I don't really see a point in elevating GNU specifically. I would argue that there is much greater importance in the Kernel itself than in the GNU coreutils. GNU was maybe important historically more than other projects, but currently it is just a tiny drop in the bucket. There are many other parts of the system that I would argue are much more significant.

Plus, even if you were right, it is just not practical. I don't think I've ever heard of anyone referring to any system as GNU, and very, very few as GNU/Linux. Everyone just uses the term Linux. Plus, it is much more descriptive. You could argue that today you can have GNU/Windows if you install cygwin, but not really sure if it would make sense to call it that. At that point you could say that Windows is GNU and for example Alpine is not. But I would really like to see someone argue that Windows has more in common with Debian, than Alpine has with Debian.

In some contexts it might make sense to refer to it as GNU/Linux, for example if you are comparing it to a distro that doesn't use GNU, but other than that I don't really see any point.