FFXIV's decline is nothing special. Every corporate franchise experiences this growth > decline cycle. Star Trek, Star Wars, Stargate, Final Fantasy, Pokemon, Harry Potter, Game of Thrones, World of Warcraft, Guild Wars... all of them. We just get to see it more up close and in real time with MMOs like WoW.



The corporate franchise death cycle:

First phase: Creation. Original book/comic/movie/game/whatever is created and is an unexpected hit, usually has a fairly low budget.
Second phase: Explosion of popularity. The corporation begins to heavily invest in sequels.
Third phase: Milking. Content is continuing to be made, but the corporation wants to increase profits by lowering costs, so the new stuff is lower budget. A lot of the original creators and writers have disappeared, usually because they've been making the same thing over and over for years and want to move on, or are being stifled by the suits behind the scenes. Writers and producers leaving is the first sign of the end. Visible people like actors leaving the show usually comes deep into the decline.
Fourth phase: Death. Audience interest has disappeared.
Fifth phase: Reboot. Time has past and now it's time to cash in on nostalgia/brand name recognition.



FF14 is in stage 3. The FF franchise arguably reached stage 4 during the 2010s and is dabbling in stage 5 with the FF7 cash grabs.

The lesson to take away from this is not to stake your happiness on corporate franchise media, as you will always be disappointed. They always peak early and go downhill. You just gotta accept that's the way this always goes. Genshin players are now waking up to this cycle too.