Not just FFXI, many MMO's have had static level caps during the entire duration of the game or for a very long time. There's upsides and downsides to such a system though. Yes, it creates a larger quantity of content accessible at the same time. However, there's commonly a high level of grind involved to get players at the top end.
Whereas with periodic increases newer players can very rapidly catch up due to steps of new gear being easily accessible. Making games like this more welcoming to newer players.
