A set of merge requests were opened that would effectively drop X.Org (X11) session support for the GNOME desktop and once that code is removed making it a Wayland-only desktop environment.
Going along with Fedora 40 looking to disable the GNOME X11 session support (and also making KDE Plasma 6 Wayland-only for Fedora), upstream GNOME is evaluating the prospect of disabling and then removing their X11 session support.
Some concerns were raised already how this could impact downstream desktops like Budgie and Pantheon that haven’t yet fully transitioned over to Wayland. In any event we’ll see where the discussions lead but it’s sure looking like 2024 will be the year that GNOME goes Wayland-only.
This is also how X11 works if you choose not to use x.org… wayland is a protocol, the equivalent you’re looking for is wlroots.
If you use wlroots, you don’t have to do any of that.
As for why kde/wlroots/gnome are separate… x.org used to have multiple implementations too, until one took over and became used everywhere. Wlroots is the equivalent to x.org, and shares many implementation details with kde, gnome is the only odd one out, and both kde and gnomes implementations only exist because they came before wlroots.