I think the patches speak for themselves: Yes, money is being reinvested. Now if they're worth it to you is another matter, and I recommend evaluating it based on that rather than speculating over SE's exact balance sheets. So!

Do you like FF14's content and updates? Do they feel worth the subscription + DLC costs to you?

If yes, then you can keep on going. If not, then you can always walk away. And it's not a permanent choice either - if you feel sometimes it's worth it and sometimes not, you can resub or unsub for those periods.