I mean different cultures will do well with different kinds of games. While a lot of japanese games seem, mundane and, strange to us, they sell incredibly fast over in Japan. I think very few RPGs sell well here cause few companies really know how to make an American RPG.
Eternal Sonata for example, was fun, but incredibly japanese. Lines like "If I kiss him, will it find him from here?" or "The eternal heat of my burning blade will cut through flesh and bone and pierce your rage-filled soul!" . . . just, sit awkwardly with most American gamers.
For the record however, Mass Effect, did very well, and was a very well refined, and INNOVATIVE rpg. It is also one of my most recommended and favorite games of all time. Just know that if you play Halo of Call of Duty, the combat isn't exactly, innovative, the game itself ties in so many deep storytelling elements, you tend to forget it's very minor flaws.