That's a remarkable lifespan for a Squenix game compared to, say, Chocobo Racing.

Squenix is held together by FFXIV and sort of assumes FFXIV is redundant and keeps making new "live service" garbage that dies early (sometimes begins dying as soon as it comes out!) and for the moment the FFXIV glue is holding the mess together. For the moment.

Much like Dragalia Lost I expect that some group will make private servers for this as I understand it was a pretty popular game. I imagine the timeline for that will take a while, but hopefully the game being in the hands of the community will breathe some new life into it like many other games who end up being fan-run.

Close the servers, sure, but just make the game offline and complete the story if it hadn't finished.

Boom, people can play the game on their own with easier free gacha pulls and then you give closure to people who maybe never got to finish it and you can rerelease it as what happens to most games.