Obviously some of those games won't be launch games, yes, but just the same I find it unlikely that they all started development in the past 6 months; I'd believe that some of them started development as DS games and switched to 3DS, though.
RPGs are probably easier to develop these days than many other genres. Don't have to worry about fine-tuning your controls or ironing out bugs with your physics. Particuarly jRPGs, where you don't have to worry about the player breaking sequences or anything like that. Trying to find all the physics/terrain glitches and such eat up a ton more time than writing out non-interactive cut scenes.
RPGs remain pretty damn constant in being quite a bit of hard work. It's been said in game development that on the average title, about 50% of the programmers spend some of their time working on the menu system. And...this is for action games from EA and Activision--games you wouldn't really associate with "OMG so many menus". Menus are just a time-consuming pain in the ass. (By comparison, physics? Use Havok, done. You can get away with only one programmer there).
Now take RPGs which are THE menu genre and...yeah. Modern RPGs also tend to have hundreds of spells and different animations for each spell, so it's not just the programming department who will be doing lots of tedious work, it's animation and art, too!
Aaaaaaanyway, dunno if this has been linked yet, but...Minesweeper RPG!
http://www.hojamaka.com/game/mamono_sweeper_easy/en.html