Wayland was created in 2008. Mir was created in 2013.

Bazaar and Git were created around the exact same time.

Unity was abandoned after a failed attempt to circumvent Gnome 3. I was actually involved with the development of Compiz and they hired Sam to work on Unity, as he was one of the masterminds behind Compiz, but again they just didn't have the vision or execution to make it work.