FFXI for PS2 is still being supported in NA (as far as we know), the issue is there are so few PS2 users, it's not worth manufacturing the Seekers of Adoulin disc or making it available for digital download (probably because they don't want flak for making it digital only since some PS2 users might like their solid discs or they feel the need to provide both physical & digital and if they can't provide one, they won't provide the other only). From what I've heard, the PS2 disc of Wings of the Goddess was pretty hard to track down and that was over 5 years ago.
Now in Japan, it's a different story. Seekers of Adoulin is coming out for PS2 and in fact, unless another expansion comes out with PS2 support, Seekers of Adoulin will be the last official release on the PS2 worldwide. The userbase for FFXI on PS2:PC in Japan isn't nearly as skewed there as it is in North America.