FFX wasn't an anomaly, not any more than FFIX or FFXII is anyway. IX was done in a style unpopular to the west, as was XII (on top of it being nothing like a normal FF). FFXIII is looking more like something appealing to the west, so the sales should be closer to FFX rather than the lower selling two. Metacritic tells nothing about how the majority feels about the game, so it shouldn't be brought into a discussion about sales.
As for the emphasis on JRPG's, many people here (including me) are a big fan of them. The consoles' potential to sell JRPG's is important to us, because that determines where the JRPG's will go. It isn't about determining the 360vPS3 sales war (at least for me).
Also, like others have mentioned, you're confusing cause and effect. JRPG's just happened to always be on the leading console, because that's where they would make the most money. If I said something like, a best-selling FPS is the key to determining a losing console, wouldn't that sound ridiculous? Even if it may seem to be the case - Goldeneye (N64), Halo (Xbox), Halo3/CoD4 (PS360), the reasoning is flawed.
