Canonical said they'd use Wayland. They decided otherwise but never bothered to tell anyone until way later. We have been assuming they'd do their share of the work needed to use Wayland. Now that Canonical finally made public that they are not going to do their share, we're stepping up.
Mir is speeding up nothing. Canonical should've made their decision known to GNOME, even if just privately. Now we have been doing work, but still thought they'd do most of it.
Blödsinn:
http://phoronix.com/forums/showthread.php?78775-GNOME-Will-Move-Full-Speed-With-Wayland-Support&p=319035#post319035