Except that that's not why Apple avoided X11. Apple decided to build their own thing because they wanted to avoid also-ran cross-compatibility with other UNIX clones, and additionally they wanted fancy antialiased font rendering which X11 didn't support at the time.
Apple built Quartz while Xorg developed Xft. A couple years in and Quartz didn't have any compelling features over Xorg, just an alien API.
It's true that X11 is terrible but nearly all of its competitors have shown themselves to be worse. Wayland wasn't practical until recently (like 2014?) when GPU memory and latency has dropped to the point where actually running a full compositor is no longer expensive. And most people using Wayland will just host an Xorg inside for X11 backwards compatibility anyway...