It's that you didn't even bother trying out most of the content in this game

Have you gotten all mounts from extreme primals?
Have you cleared Ultimate?
Have you leveled every job to 90? (Including crafting and gathering)
Have you tried Mahjong, Verminion, and Chocobo racing?
Have you acquired all relics?
What is your achievement score?
Have you gone back into old raids at minimum item level?
Have you RPed with other people?
Have you maxed out shared FATE?
Have you cleared PotD and HoH solo?
Have you gotten 10/10/10 Valor stacks in Bozja?
Have you finished all Bozja duels?
Have you finished all sidequests in the world for the story?

There's plenty of content in this game, you just aren't willing to do it, so stop complaining. With so much content, if you are still complaining that there's none, it's a you problem.