It feels like it to me, but my understanding of how things work in this area is pretty limited. I've been using Xubuntu for a long time now, does it currently depend heavily on X.org? I'm having a hard time figuring that out searching the past 20 minutes.
Pretty much every Linux desktop GUI's been on top of the X Window System—which has been synonymous with the Xorg implementation thereof for, oh, 15ish years now—until very recently. Red Hat's behind a totally different replacement for X Window (and so, Xorg) called Wayland, but desktop environments that run on top of X Org will require major work to move them over to it, and most haven't done that yet, if they ever will. Last I checked Wayland's also a bit half baked at this point, from a "does it work with all my stuff and do all the things I'm used to" perspective, so news that it's the only system receiving new feature development means some risk of a fairly awkward transition period.
Notably, I think you still can't get hardware acceleration under Wayland for nvidia cards, making it unusable. Yeah that's nvidia's "fault" but to the end user it makes no difference if they upgrade their distro, the distro switches from Xorg to Wayland, and suddenly their computer sucks.
> you still can't get hardware acceleration under Wayland for nvidia cards, making it unusable
Nvidia wrote patches for GNOME and KDE to support their crappy custom EGLStreams thing alongside the usual GBM. I think GNOME and KDE have accepted them.
Porting XFCE applications (Thunar etc.) to GTK3 indeed gives automatic (or near-automatic) Wayland support. This means that XFCE applications will run natively (without XWayland) in Wayland compositors (such as sway, GNOME or KDE).
However, xfwm (the window manager) will also need to be ported to Wayland — i.e. become a Wayland compositor — which will probably be a more complicated undertaking, as "xfwm-wayland will need to fulfil the role of both X and the window manager. (Yes, using libraries like wlroots or libmir, will make this not completely impossible, but it will still be non-trivial.) Plausibly, XFCE might join forces and use the same Wayland compositor as, say, LXQt or Mate.
I believe so - Xubuntu is based on XFCE, which is an X based environment. I've seen some mutterings that they may eventually write a Wayland backend, but I don't think that it's in the near future
