I always got the impression that it was a backwater sort of world, set aside specially for keyblade-master training, kind of a bit like jedi, only on a little world of their own. And that once upon a time it was thriving with people but after, you know, the keyblade war, not so much. And now it's pretty much Eraqus and his kids students. :( Pretty lonely, for him!

Possibly the world got injured in the war, too? So, stopgap measure, particularly since they wouldn't have had a whole lotta manpower, afterwards. And then it was just there, and it worked...