> There are X extensions for shared memory buffers. Client isolation for X could also have been implemented as some kind of extension. With both of those you could solve some issues but it still wouldn't be the same as redesigning the core protocol.

So why redesign the core protocol if the selling points of Wayland can be had without going through all that hassle? What are the true selling points of transitioning to Wayland, if they can be had for far less work?

> Yes this might cause some fragmentation but realistically, has X really helped there? The huge proliferation of clones and forks of various X window managers that are incompatible in various ways is another kind of fragmentation.

There was only ever one dominant X server implementation for the past 30 years (XFree86, then X.org), so yes, I'd say it helped a lot to keep the video/input multiplexing system out of the hands of window manager and desktop environment developers. This ensured that your graphical programs would always work, regardless of what desktop environment or window manager you used, because they all spoke the same protocol and relied on the same reference implementation. A proliferation of Wayland compositors would take all of that away.