Basically they're building their own X replacement even though there is one in the works (Wayland) that they admit fits their needs (or could if they worked on Wayland), simply so they can have control over it. They also admit that they aren't going to bother to make it work for anyone but them, nor are they going to worry about a stable API for it (because in their minds it's only used internally, they don't care about external people who are trying to build compliance with it).
Basically they're building their own X replacement even though there is one in the works (Wayland) that they admit fits their needs (or could if they worked on Wayland), simply so they can have control over it. They also admit that they aren't going to bother to make it work for anyone but them, nor are they going to worry about a stable API for it (because in their minds it's only used internally, they don't care about external people who are trying to build compliance with it).