A switch to F2P (mostly full-featured with cash shops for boosts/cosmetics/etc) with the paid accounts getting even bigger perks would be a shot in the arm for FFXI. Couple it with termination of PS2/360 support and I could see the old girl hang on for another decade or more. I don't see any reason to fear F2P if that's the direction SE wants to take the game to help it survive.
I have to disagree, XI will probably last another 3 years, that's being generous. Before Seekers, the content was getting stale, people were getting bored and losing interest on top of those who had left after disapproval of the Abyssea mini-expansions and never came back. When Seekers hit and the data mining started and the R/M/E issue blew up something new happened; JP started leaving in large numbers. Everything was just "ok, we'll look at what we can do" with a thumbs up and a fake smile when NA and EU were complaining and quitting over all their effort being for nothing, but when JP started unsubbing they listened. I don't think Matsui fully understood what his dropping of R/M/E would mean for the game.
Think about it; they are just weapons with unique appearances and a (usually) novelty weaponskill. But to some Relics were kind of a symbol. Back in 2005~ if you got one and someone saw you with it, everyone knew within a matter of hours, Matsui failed to realize that a relic weapon had become a symbol to many, for those who had them it was a symbol of their hard work and effort put forth and perhaps a symbol of friendship between them and those who helped them obtain it and for those who didn't have one they were goals. By the time Matsui rushed out a few examples, the damage was done.
Some went back but I know pretty much my entire LS quit as did most of the people I knew. FFXI came to be a game I played not just to make progress, I played it to be with my friends. The truth is, I wasn't far from cancelling my sub when a former LS mate contacted me on here and invited me to a LS. That LS was my final LS in FFXI, I made great friends in there, we had great laughs, that's why I played. But they are all gone now and so am I, I have no desire to go on without my buddies.