Not when almost all of that user base is top heavy (i.e. already level capped, no reason to play with newbies).
Not when the engine is over 10 years old, even if PS2 support was killed the engine still has limits because it was built on the specs of a PS2 (full engine rebuild is needed where 14 can get away with a revamp due to a newer core engine).
Not when a revamp risks losing the current established user base because the changes are unwelcome. (If the BST pet poll is any testament to how SE really listens to the players this is highly likely.)
Not when a revamp involves a lot of existing content and story lines.
There are more reasons but these are fairly major reasons why revamping 11 isn't as financially feasible as 14.
