Short answers, pulled from the story.
The original Final Fantasy XIV failed because the development team over-prioritized graphical quality at the expense of server performance, lacked experience with modern MMORPGs, and believed problems could be fixed in future patches. Director Naoki Yoshida identified these three causes at the Game Developers Conference in 2014.
Final Fantasy XIV: A Realm Reborn was directed and produced by Naoki Yoshida, who had previously served as planning chief on Dragon Quest X. He was brought in after the original director Nobuaki Komoto was demoted and producer Hiromichi Tanaka was removed following the failed 2010 launch.
Early access for Final Fantasy XIV: A Realm Reborn began on the 24th of August 2013, with the official worldwide launch on the 27th of August 2013, for PlayStation 3 and Windows. The game was so popular at launch that Square Enix temporarily suspended digital sales because servers could not handle the number of concurrent players.
Final Fantasy XIV reached over 24 million registered players by October 2021, at which point it became the most profitable game in the Final Fantasy series. The lifetime total grew to 30 million registered players by January 2024.
Final Fantasy XIV has six expansion packs: Heavensward (2015), Stormblood (2017), Shadowbringers (2019), Endwalker (2021), Dawntrail (2024), and Evercold, set for January 2027. Each expansion raises the level cap and introduces new zones, jobs, and story content.
Masayoshi Soken composed the majority of the music for Final Fantasy XIV: A Realm Reborn while also serving as sound director. The soundtrack, released on the 21st of March 2014, on Blu-ray Disc, contains 119 tracks. In 2017, Guinness World Records awarded Final Fantasy XIV for having the most original pieces of music in a video game, at nearly 400 tracks.