Subscription should be to improve FF, not just make other games.

[NaoSen]

When FF14 Mobile comes out with things such as Chocobo unlock at MSQ level 5, Teleport direct to Aetheryte shards, a better gpose system, a better glam system, a friends system that actually functions well, in game voice chat and a better netcode making it feel more responsive it's pretty hard to justify the Buy to play + Sub + Store model of the console/pc version.
Yes ones brand new and ones on a spaghetti code foundation however that excuse can only go so far, at some point you have to just suck it up and take from that huge income stream and fix the game you have a 10 year plan for.

Edit:

The reason why SE can't find developers is that their process involves crazy code debt and bad legacy systems - no fresh blood will deal with this.

CCP Games had a similar situation with Eve Online, the developers who worked on an entire system had since moved on and its code wasn't in English either so no-one could even understand it as fresh blood were mostly english speakers, they eventually re-wrote an entirely new system to replace it with new features etc... At the time of re-write their average online player base was 35 000 players.
It can be done, you just have to care enough about your product to invest in its future, they could bring in new talent to work on replacing old with new to build a new foundation for the future. It's a lot easier to just have to understand how you need to plug your new system in than modify an old.