To everybody trying to say that every MMORPG on the market does this: there's a big difference from keeping content of the expansion locked/inaccessible, and the content not even existing in the first place.
All of the people that are pointing at Final Fantasy XI are guilty of mixing the two up. Both Rise of the Zilart & Chains of Promathia were completed before shipping (as complete as MMO content can come, at least, considering things are always being tweaked), only Square Enix slowly unlocked things via the bi-monthly updates. They do this for varying reasons, among which would be to keep as balanced a playing field as they possibly could, to keep fresh content hitting the game up until the next expansion was ready to hit, to prevent power-gamers from burning through the content in a matter of weeks and quitting, etc...
So while I can't speak for the Lineage series, or most other MMOs given my lack of experience, I have to say that the accusations that "Final Fantasy XI does the same thing!" are totally baseless. After all, Square Enix isn't sitting in their little workshop, counting up their subscriptions and going "OK, we finally made 100,000$... We can finally afford to add the Diablos summon!," despite whatever you guys would like to believe.
If you need proof: did you ever happen to notice that the updates that unlock CoP content, are roughly the same size as the updates that hit after RoZ was fully unlocked, and before CoP was released? You know, the updates that contained absolutely no expansion content what-so-ever? Yeah...
