That and WRPGs have just been scoring more favorable reviews.
Oblivion, Mass Effect, Fallout 3 and possibly even Dragon Age Origins will all score 90+ on Gamerakings. Hell, even Fable 2 has a 88%.
Tales of Vesperia is the only JRPG to maintain a 80% or higher this gen, while Lost Odyssey and Eternal Sonata came close they are considered just above average from most critics point of view.
I am speaking for the 360 of course. I know VC, Demon Souls and Eternal Sonata re-dux have above a 80% on the PS3.
It's just that simple.