That’s more or less what we tried to do. The problem is that you can’t feasibly put the old thing on maintenance mode unless you have the manpower to push the new thing to completion very quickly, which it unfortunately turned out we did not have. Also “maintenance mode” is not the same thing as “unmaintained,” which means people still need to work on X11 support during the transition, which further reduces the number of people available to work on Wayland support.