A large part of the issue is the design direction of the game essentially being built like a single player with optional player slots for friends in most content. It also resulted in a heavy story driven focus with your character as the unstoppable hero that hardly ever acknowledges the existence of other players outside of a handful of cutscenes where they told you to find allies before a trial or something. Also the actual overworld is severely lacking in staying power for players as the zones mostly end up as ghost towns once the story moves away from them and players have bought all the things they want from the crystal vendors or gotten their drops from the super fates. There are also convenience features like duty finder which eliminated the need to travel to duty entrances after unlocking them the first time so people can just lounge around all day in a town, FC house, private house, etc and queue duties.