Why does xorg still exist?

I am familiar with the development history of xorg. I am not learned as to the history of failed projects to replace it. What replacements were proposed before Mir and Wayland and why did they fail? They couldn't have been that bad. Wayland is as bad as xorg if not worse by its lack of standard implementation alone and it received financial backing.

>>1
Wayland received financial backing because Red Hat is pushing hard to replace the linux graphics stack with something it controls.

>>4
It's so slow Gvim is more responsive on Windows than it is on Linux https://pavelfatin.com/typing-with-pleasure/ .