As for the rest of your post, I am in a situation somewhat comparable. I usually play games that I personally like, but the ones I stick to are those where I can play with friends (not necessarily RL friends, but friendly individuals that I like). My FC (60+ people) is the result of a pretty massive achievement that I was so glad we could pull off with my best friend: we literally gathered pretty much everyone that we knew and was playing MMORPG's currently, and made it so there was no restriction whatsoever to join so people could invite their friends ("+1's" as we say IRL when your invitation allows you to bring a friend to a party). +1's, +2's… the thing got somewhat much bigger than we expected (we didn't do any traditional 'recruitment' in-game to gather 60+ people, it's all 'friends of friends'). It's just sooo great in and out of itself ^.^ We simply let people self-organise, so that hardcores are running Coil and helping others do Titan, whereas the more casual crowd is simply enjoying the game at their pace (we ran tons of low-level dungeons so that people only resort to using DF as rarely as possible; not that we're against DF but it's just nicer/funnier to play with friends, obviously).
Regardless of how much they play (which has more to do with RL than IG considerations), we have two kinds of players: die-hard FF fans, some of whom were still in FFXI until early 2013; and all-around MMO'ers/gamers obviously more likely to hop from a game to the next. I don't think I need to tell you which of these two kinds is starting to leave the game, be it to clear their GTA V, enjoy their PS4 and whatnots. I belong to this latter group (never played XI as I was leading in or exploring other games, and I tried pretty a good deal of the AAA MMO's released since the last decade, though these last years I didn't play a lot since I took back uni courses besides work). I'm feel quite sorry leaving this great gathering, I really wish it were otherwise. But I'm already thinking of the next step, organising our foray into ESO most likely (not really hyped up by Wildstar personally), and obviously SC (though I know this game is quite specific a genre and won't cater to many players, it being a sandbox horizontal progression MMO based entirely on skill). But I'm a sci-fi fan so I just can't pass on this incredible occasion to ride a spaceship >_> … haha
I'm feeling we're kinda off topic here, it would have been better to discuss all of this via pm or something but since we can't, well, I just wanted to respond.