I honestly think that FF17 is being developed full-time and aims to replace FF14 as a live-service title. We've already seen what's happened to FFXIV since EW released when most of CSIII was put to work on FF16, and you're telling me they just went back to FF14 afterwards when it's main saga was finished? No way, they have to be working on something else. And while it remains to be determined whether a traditional MMO would be a good decision or not in 2025, I think FF17 could easily be a different time of live service game given that a "massively multiplayer online game" is a bit more broad than it used to be these days. Either way, FF14 has had its day, it's main story is over, and while it's likely to be supported for some time to come just like FF11 was, I don't think it's unnatural to assume content updates will become much more sparse.