I doubt it's their goal, but I'm sure they realize it's a not-insignificant part of the playerbase even now, and it's not different from most other competing MMOs as well (e.g. people going back to prep for the WoW expansion now). There's an audience of players who just don't like the MMO endgame routine in general (regardless of whether it's WoW, FFXIV, or whatever else), but still enjoy the story and playing for a time.
It's financially successful by SE's own admission in their earnings, not just because it's long-lived. Obviously, years with expansions are even more financially successful, due both to expansion sales and increased amount of players coming back or joining to experience it. That said, the subscription model is there to provide stability as well (like why a lot of software companies are trying to move towards subscriptions), so obviously they need that too (or some other way to provide on-going revenue to fund content development).
Honestly, there's no simple solution to the retention problem. This game is a vertical progression theme park MMO, and there's only so many ways they can mask the simple reality that, in all vertical progression MMOs, the gear you earn will eventually be useless except as glamour. This is ultimately what burns people out from every vertical progression MMO. They can do things like 8-person dungeons, differing levels of difficulty/time attacks, and instances with other different kind of gameplay mechanics (and I believe they should do these things, to be clear), but these are still just gimmicks that won't really mask the fundamental problem that burns people out, ultimately. Of course, this problem is also the sub-genre's greatest benefit.
I just don't think I've seen any game in this sub-genre really ever solve this "dedicated player ennui" problem. There's never enough content, and the sense of "pointlessness" eventually settles in, except when your experience is driven more by the people you play with and those social connections become the real content that keeps you engaged. Horizontal progression MMOs, on the other hand, tended to foster more long-term engagement from dedicated players (since you could always work on your own objective that wouldn't just be rendered pointless in six months), but at cost of accessibility to new/casual players. People are pitching this as a FFXIV problem (and sure they could do more to obfuscate the pattern), but fundamentally it's a trademark problem of this design approach in every game that's used it (at least in my experience, anyway).