Expansion/Updates Timeline?

[Nora_of_Mira]

Have they come out and said it'd happen every two years, or is that just the way the winds have blown since the game started?

FFxiv is only able to produce their amount of content thanks to their pre-determined content cycle, so they have said. So yes, you can expect a major patch (new story quests, trials, raids, dungeons, etc) about every 3-4 months with random things in between like job adjustments and experimental content.