More than this, it's content for its own sake.
Raids, dungeons, trials, job quests, MSQ, more jobs, seasonal events, crossovers, zones, crafting stuff, QoL upgrades - I can get behind all that. As well as this, there is maintenance and improvement of things like the netcode, server infrastructure, job balance and also possible graphics and customisation options... and, dare I say, reviewing the 2.0 quest structure. These are all things the game has a good reputation for and which are essential elements of its content.
Hot messes like the game's PVP, diadem, BLU, the implementation of Eureka, as well as very rarely used content like the majority of Gold Saucer games or squadrons? What about HoH? Should these not be subjected to a value for money rationalisation? Now, I can't say that they haven't done that, and would hope that they have, but there is a mountain of already existing content that, if they did not lift another finger, would still be there. Meanwhile, we know that even if they did perform such a rationalisation, they have probably erred in terms of assessing the value of some content, e.g. Diadem was widely considered a failure. It's not so much that an MMO can't spread out over various forms of content, just that other MMOs either have larger budgets to do so (i.e. see greater re-investment), can do so at a lower cost due to fewer legacy issues or focus on specific areas which they want to excel at. If the resources are as tight as they claim, then why are they going on these failed projects? Moreover, do they lack confidence in their marketing schemes like the Dad of Light movie?
Could be they think it will expand the playerbase and bring in more money, so they're waiting to see how it turns out before committing to anything yet, which is fine, but there is clearly content and "content".
This is a sub MMO with a cash shop that by all accounts brings in considerable revenues for very little effort. So where is SE diverting all this resource to?
Unfortunately they're working with a difficult situation, because the game has a lot of legacy issues, but that can't act as a constant impediment to bringing it up to current standards.
It's more that I think it's presumptuous to believe that the whole affair can be shoehorned into that.