Yeah the same thing happened to me. It's the most jaw-dropping, 10 minute cinematic but you can miss it so easily.
Ah yes, "The End of an Era". The first half of that cinematic was originally played for all of the players the moment when 1.0's servers were turned off, as the climax of the Seventh Umbral Era plot. In that sense, it is the ending cinematic for 1.0. Shortly afterwards it was used as a promotional video. It really is the best cinematic sequence Square Enix has ever produced. The second half of of the video is new for 2.0, though.
The answer is more story. The developers have been extending the game's plot with each major patch. Furthermore, the game's endgame content often has well-fleshed out story of its own. Both Crystal Tower and The Binding Coil seem to have independent story-lines that progress as you clear the dungeons.So I am really enjoying this game but I'm wondering, what is the motivation to keep playing after the story?
Though the end-game dungeons are just plain fun to experience, in my opinion. Most of my favorite dungeons in the game are in the endgame: Copperbell Hard Mode, The Lost City of Amdapor, and The Labyrinth of the Ancients.