I always find that with GNOME it seems like super basic features that should be included are made as extensions instead, which wouldn't be a huge deal except that the extensions update completely independently of GNOME and each other, with no regard for cohesiveness or compatibility. Every time I've run a machine with GNOME it feels like there's always at least one extension broken at any given moment meaning there's always something vaguely irritating going on.

I like GNOME because it's got everything I need and nothing else. I've got ADHD, so any distractions are really a problem.

With KDE I have the feeling that it's kind of "full". I have always been able to customize Gnome in whatever way I've needed, but that's less in-your-face than in KDE.
It's also a matter of what I've gotten used to. I started using desktop Linux with Redhat 5.2, and that came with Gnome. So, I got used to it, and KDE is different. And of course, KDE might have changed in the last 10-ish years, which, I think, is how long time ago I touched a KDE desktop at all.
But, since I'm happy with GNOME – and, this might sound scary – actually even happier with Unity that I'm using now, I don't really have any need to venture to try anything else.

It works for me and switching to something else would require at least some amount of effort.
I'm already being less active with my children than I would like to, so I don't like putting any effort into things that won't really bring something useful for me or others. I prefer spending that effort for being a better father :)

I think it's mostly former apple users who like gnome (gnome 3 era anyway) the most, since to them MacOS looks awkward and slow.

Those users are shown too much in one go kde, lock up and scare themselves away from it.

KDE really needs to change how they introduce new users to it if they want to gain new users. The troubles this user had in KDE will actually help them do that in a small way, but they need more footage of first time users explaining what they are trying to do to help them see what's actually confusing of not obvious your first time around.