No. Most distros have their primary DE. Ubuntu uses Gnome. And Kubuntu doesn't count as a different distro.

"Seems" doing a lot of heavy lifting here.

Plenty of gnome users just use it. No reason to talk about it and lord it over anything else.

Eh, Ubuntu (definition: can't configure Debian for us oldies) is just a waystation to better Linux places. It's saving grace was compatibility to weird and wonderful hardware, 'just works'. That's long since been rolled into the kernel, any distro will work with most things.

I gave my kid a bazzite installer when their old motherboard died and they didn't want to buy M$ again, literally zero issues. Was expecting some, but no, everything they use was fine, or at least they worked it out without my input, proud parent moment. I occasionally give them hints as to how powerful it is, but they don't care, and that's great.

It is for me 🙂

I won't happen. If you prefer KDE you should pick another distro. One that doesn't have an official DE (Debian, etc) or one gives KDE a primary role (OpenSUSE, etc).

Simply no. Canonical always used GNOME and I don't see that's changing.

From the user's point of view, if you discovered KDE you might have discover other distros as well. Kubuntu still be your start point though, or even where you settle.

No. There are two major DEs and it's them. I see neither is going anywhere and more often than not, both are offered to choose from. I think GNOME is often picked as the default because it's all about simplicity and that makes sense for business-oriented distros like Ubuntu and Fedora

When I say Ubuntu I’m typically talking about the Docker image or a VPS’ (non-desktop) server OS. I don’t want to use Ubuntu as a desktop OS so I’ve never given KDE vs GNOME thought at all.