I don't think anyone struggles to realize that Xwayland is still going to be around. It has to be or RHEL 10 would fail to run less than half of the enterprise software it needs to stay in business.
My first reaction to that was, they'll probably do that limitedly for servers, which don't need graphical acceleration, but since they want to make it mainstream, they'll need graphics capabilities as you've implied.
Xwayland is equivalent to Xephyr but you probably don't run your Window Manager of choice in a nested Xephyr session do you? Do you know anyone who does? Imagine that KDE could only run in an Xnest / Xephyr instance so couldn't actually handle any of the windows that pop up natively. Would that be a good experience? This is what a user running Mwm, Fvwm and other standard Window Managers would face.
Wayland can currently run on the X11 desktop like a Xephyr window, but on its own instead. Last year, I stumbled on a way to run a second X11 window manager (it wasn't Wayland) in a second virtual terminal on Ctrl-Alt-F10, I didn't write down the notes on how I did it, and I couldn't do it again.
These are all good things to think about. Effectively a libW11 (Xlib API but Wayland hooks underneath) will be useful to port software (and I am actually shocked that the Wayland ecosystem has *nothing* like this in place after almost two decades). However I fear this will simply allow for replacement of Xwayland over time rather than keeping Window Managers and the whole X11 flexibility alive. We need something to at the very least help port X11 Window Managers over. Perhaps a Wayland compositor that exposes an Xlib API as a way to add decorations?
In the text and arrow example, it was about forking Xorg instead to trim out legacy parts, and figure out how to make it modular, with what can be learned from Wayland. Then, making a compatibility layer for Wayland graphical toolkits to run on this version of Xorg. We may not need Wayland compositor layers, as we would be depending on X11 window managers or perhaps a new invention of X11 compositors.
A trimmed down Xorg would be easier to maintain. And keep parts modular. Also, if an Xorg fork gets going, keep standards like the old one, except drop the legacy ones. There can be a standard that it builds with the FreeBSD toolchain or with meson. In addition, there's parts we can get from NetBSD like gettext. Maybe find a steward, perhaps find a way for multiple BSD's to steward it, in addition if the old Xorg also wants to be of the fork. FreeDesktop is too Linuxy, as the X.org blog shows an X org subdomain, but instead goes to
https://planet.freedesktop.org/.
libx runs on top of parts of libxcb, while rest of it lies side by side having two different ways. libxcb strips out many parts of libx that aren't needed, so the libraries are more compact, however, too many libraries are lacking, that libxcb can't fully replace libx any time soon. Keeping it modular and making it easier to strip out libx parts will allow a cleaner transition for the future.
Here's a diagram of X11, which I haven't made sense of yet model wise:
This chart is at
https://www.x.org/wiki/guide/concepts/
The other chart diagram in my previous post, wasn't of that, it was from Wayland's page.
Now, going back to another topic of X11 on Wayland, if Wayland doesn't have a way to for a compositor to have reparenting, then that would mean Wayland would have to be forked, or convince them to have limited ways to allow reparenting, so that there can be controls put inside of Wayland. So that would be hooks reaching inside of Wayland. A libw11 sounds good, even if we aren't sure yet what it would be.