FATEs are killing Dungeons and team play

[Felessan]

the problem with FATES is theyre so good theres no point in any oyther content

It's only a shortcut for those who don't want to grind quests. You actually can't skip dungeons, as merely "level 50" means nothing. You need to complete storyline to get access to AK/Primals Hard, and this imply doing quite a few dungeons.
Most of the quests are repetitive, dull and uninspiring to do especially as healing class, so trading them off to FATE is same-for-same trade. (not pointing to the fact, that grinding quests gives you more exp that grinding FATEs)

All of the people rushing to the "end game" content will leave soon enough, once they hit that cap.

They will hit the wall of "end-game access requirements" and will have a choice to either leave or go back and redo all that they missed. Many choose second route still.