I mean people leave. it happens. The problem is that there's no one who left in 3.0 or as a result of 3.0 that have really come back yet. You won't see people coming back in droves, I feel, until 4.0. It's really up to the team to make 4.0 something that retains players better than 3.0 has. It could be a turning point for this game in terms of its longevity.
It feels like more and more veterans are leaving still, but we're only getting newcomers joining up rather than veteran players returning from an absence. Like most MMOs, once you take that fist big break, it's very hard to get back in again. Even if you do, it's not the same sometimes. This is the ultimate fate/cycle of all MMOs (and online games). Veterans leave, the rate increases over time, and the rate of newcomers declines too to the point where the incoming < departing. The spiral of death for an MMO which usually isn't recoverable (even WoW is in this phase now, and while expansions give a temporary boost, it's still overall on a downward path that doesn't seem like they'll be able to break). It's just how all MMOs end. I kinda believe XIV has hit that. Obviously this doesn't have to have any serious impact on XIV's service -- XI is still going after all -- so safe to say XIV will be around till probably 5.0 at least, likely beyond that. However, servers will truly be dead sometime after 4.0's "boost" ends IMO, around 4.1 or 4.3 I wouldn't be surprised to see server merges.
So while the game may continue largely unaffected, it does mean some veterans interested in end game content get to deal with the pyramid scheme. On Ultros right now, there's a lack of groups doing raid in general, I'd argue it's at its lowest point ever. If your group suffers serious losses, like the one I was in just did a week ago, you're screwed. You have to break up and each on your own try to find a new group, or try to replace a significant amount of members, which can take time (especially on Ultros). It used to be you could find people around your level/progression pretty easily until some point after the A3S blows ups began September/October. Since then, it's been down hill. There has been a slight bump I would say with 3.2, but we're already seeing the decline again as more groups hit A6S. Last raid cycle burnt people out too much I think, including me, and I don't want to sit on a turn forever again. Nor do we want to go backwards too much. Right now you can probably easily find an A5S group, or a group just starting A6S, but anything beyond 2nd robot on Ultros is non-existent. The groups on that are locked, the pool of people cut out from that for various reasons (ie group break ups) can't refill. The're forced to go back to earlier in A6S, and some people (like me), can't deal with that/don't want to waste time on that frustration again.
Obviously, for others, this might not be the experience. But it's been mine. Which is hwy I'm aggressively looking to move servers if I can find the right group. I love GAF, but GAF has been in decline activity wise for some time now. Outside a very few things, most of the activity doesn't interest me. We don't have a large PVP following/focus, the few who care about it are in PVP LS anyway and that's enough. Same with raiding. I think there's what, 1-2 completely all-GAF groups anymore? Not that it matters if everyone is from GAF, but at one point during coil days, GAF had a ton of active raid groups and was pretty interested in raiding in general. That just leaves the social end of it, which is good when it's active, but as a whole Ultros' activity is down, and GAF's social activity is probably at its lowest ever.
So the hard, convincing reasons to stick around on Ultros are fading by the day. I play this game to raid (and make progress, not bang head against wall cuz certain raid members can't learn mechanics after so much time or DPS is too low even after pointing it out). So in regards to actual serious raiding, maybe I am a bit of an elitist and have higher expectations. After running with certain groups, I got a taste of it, I enjoyed it, its what I want. Without it, I just get angry, frustrated, and annoyed at this game. So it's either go find a solution to this, or why am I still bothering to play this game. I can make up excuses for only so long to stick around here and say it will get better, but I think deep down I might have accepted the heyday of Ultros has long since past, and it's never coming back. It's gone to other places. And even deeper down, the appeal of XIV is dwindling, and unless some miracle happens in 4.0 (ie the whole campaign is based around FF IV, the best FF ever or something of equally awesome magnitude), the days ahead of me are definitely fewer than the ones behind me. /endrant