The weak dollar makes FFXI really cheap for me here in Norway.
If you think the few megabytes your character profile takes up is all that costs for an MMORPG company, you are very mistaken. Sure, they make a profit, that's one of the main goals of any company anyway, but a game server is much more expensive to both run and maintain than a regular home computer, and both Blizzard and Square-Enix has a couple of dozens of these. Then add in backup systems and bandwidth costs, don't think you can get away with using the CEO's home ADSL

. It needs to be both extremely stable, and have a lot of bandwidth. After all that, we need to consider hardware faults. Do you know what the average lifetime of a hard disk in a server is? It's something like 3-4 years, meaning a ton of hard drives have been replaced already at S-E, seeing as this game has been running for over 4 years now. I don't know about S-E, but it is not uncommon for a server to have two hard drives for redundancy, and in addition, the hard drives are often faster than those used in desktops.
Considering all this, and the fact that they will want to make a profit of their games, I don't think 13 dollars a month is a too much to ask for at all.