Wayland is a protocol that can be implemented by a compositor. Since Wayland intentionally chose to only support a subset of the functionality of a display server like Xorg, it became possible to rip out the Xorg specific hardware drivers and make the X11-supporting Wayland compositor known as XWayland possible in the first place.

"We're stuck with just a protocol that can have arbitrary implementations including full backwards compatible X11 servers"

The words "full backwards compatible" are not entirely true in my experience.

X11 is ancient history and not a fit for tiling GPUs found in mobiles socs

Sure, but all the software I want to run uses X instead of Wayland. And it would be cool if we could get reliable key remapping under systemd and wayland.