Exactly the streamers come and go and their flock follows them …form what I have seen so far FFXIV devs are going with the plan if they can keep the streamer happy then he and his fanbase will stick around. However all it takes is one new game offering a better deal, one day of boredom, one fight and those streamers could be out the door and their fans with them.
However if you to create a TRUE community you need fans of the GAME not the people playing it.