> There is no support for accessibility for the visually (or otherwise) disabled in KDE Plasma's wayland extensions (and none in core wayland at all

Can you clarify what you mean by this? In the process of KDE implementing Wayland support I also have seen several issues and blog posts dedicated to accessibility features. In fact, I am fairly sure I saw KDE explicitly funding accessibility development in relation Wayland a while ago.

I am using KDE with Wayland and just had a look in my settings and the Accessibility menu is there and the features in there also appear to be working. Including the screenreader which worked on all windows I had open at the time.

Which makes sense as none of that goes through the display server but rather a D-Bus protocol implemented by Qt and GTK as far as my understanding goes.

There is a bunch of stuff that came with X11 "for free" like access easier screen capture for magnifiers, input injection, etc but as far as my understanding goes KDE (just like GNOME) has been working on DE specific implementations of each.

I am not saying things are perfect right now as far as accessibility goes. I am not someone who depends on these features. I also know that things are in fact not perfect across the board and there is still work to be done. But the claim that there is no support for accessibility seems like a rather large hyperbole to me.