Estella Vanilla
Fashionista
FFXI Online was first released in 2001 in Japan, and 2003 rest of the world. FFXI Online is already a game that has been out for a quite long time and mmorpgs that are out that long will just lose players till the end because you'll get very bored =/ ...
You're forgetting that they don't really care if you're bored with the game. If you've been playing it for a least 2 months they've already made enough money that they'd get by purchasing a normal game. Add on the monthly subscription and they've accumulated tons of money from that game over the years. It doesn't matter if they lose players, they constantly gain them to make up for it.
And I'm not that sure this will be a PS3 exclusive. FFXI was just PS2 and PC then Xbox was added on after a while. I wouldn't be surprised if they added it on again.