That is not a valid comparison. 500k was FFXI's maximum subscriber base. 500k is the "active" number for the FFXIV census, which includes only characters that have completed the level 65 dungeon. There are many paying subscribers who have not done that. I attempted an apples-to-apples comparison on this thread:
http://forum.square-enix.com/ffxiv/t...83#post4547683. To be fair, I assume far more people complete content in FFXIV than did in FFXI, but even given that, FFXIV's endgame community is several times the size of FFXI's.