CoP itself took months to be completed through several patch updates. It wasn't all released in one chunk. Heavensward had a story from start to finish with the launch of the expansion. The only reason Zilart even had something similar was because the North American launch was months after the JP release. Dynamis, Limbus, etc were also added, but again through several patches.

http://www.zam.com/wiki/Update_History_%28FFXI%29