FFXI makes them tons of money. Even if it needs a whole new transmission and a paint job, it is still worth the investment.
The number of capped players is irrelevant. The number of new players playing with each other is what matters. A remade FFXIV has no more potential than a remade FFXI for getting new players, possibly less due to it's bad reputation. however, FFXI already has more players, so if no new ones come, guess what......it's still profitable.
The FFXIV road map says this:
1. A complete redesign of current repetitive maps
2. The implementation of a new graphics engine
3. A new server system designed for increased speed and performance
4. A fully renewed user interface
exactly what engine are you talking about that isn't getting rebuilt? and what makes you think that it is any cheaper to do it to FFXIV than it is to FFXI?
