Been playing since ff14 1.0 (beta) and I still enjoy my time with FF14. Sure I am not subbed 100% of the time and have phases where I concentrate more on my job or other games. But that is the majority of players.
The people who play 1 game religiously do all the content they can in the shortest amount of time is a very minor part of each mmo community. And while it sucks for that part of the community it is definitely not the focus when it comes to production planning.
As someone who works in game dev myself I can't tell you how happy I am about the FF14 team's approach to development. It's a quick enough pace to keep things fresh but not quick enough all the content they introduce feels rushed an unfinished.
Obviously that doesn't mean that I agree with all the design decisions but that is okay.