You are technically correct (I know) but I would argue that distros that come with a certain DE usually have their experience built into it. Sure you can install gnome in kde neon but don’t expect anything to work, if it does it’s mostly by accident.
This is true for distros that cater to “simple” users that want to install and be productive of course, not for those like Debian or arch which cater to users who want to build their own experience.