Ubuntu's main source of income really wasn't in the desktop. It makes good business sense to switch to GNOME and have the community run it for you. What Canonical has done now has really lifted a weight off the Linux community's shoulders. Now that the corporate backing has dried up, we can go back to supporting things like Wayland, rather than trying to compete with them. Competition is good, but when it comes to something as complicated as display protocols, it's good to agree on a standard.