The fact that XWayland's "performance should be roughly on-par with native X11" probably solidifies rather than weakens the position of X11 as the de facto display protocol.

If everything that uses X11 today can be used on top of XWayland without any modification and without performance loss, this means that a lot of pressure stemming from the need to switch to speaking Wayland instead of X11 is lifted in a certain sense.

Or am I missing something?