Otakuness has nothing to do with it. Experience had a solid hit with Demon Gaze and they've been pumping out games since. With their quick development cycles, maybe the dungeon crawler genre is getting a little oversaturated, especially considering how much of a timesink they are. It did have a better opening week than Operation Babel though.
[PSV] Demon Gaze (Kadokawa Games, 01/24/13) – 25,316 (New)
[PSV] Tokyo New World Record: Operation Abyss (5pb., 07/24/14) – 15,242 (New)
[PSV] The Stranger of Sword City: Black Palace (Experience, 01/22/15) – 11,559 (New)
[PSV] Operation Babel: New Tokyo Legacy (5pb., 04/30/15) – 8,104 (New)