But what audience to they have on that platform that don't play TES on PC, PS3, 360? Will the returns be worth the effort?
same reason you would release a game on pc even though it's been months sience it's console release, there is still plenty of market for it.
Aswell as the fact that not EVERYONE will buy Skyrim, tapping into a next gen console where they can bump up the graphics to pc levels is probably why it would sell.
Believe it or not but people do buy the same game twice sometimes, and Nintendo now that i think of it has a HUGE market for RPG's.