(such a strange topic, still, interesting)
funnily enough, google comes up with
cultural differences between US/JP games on Wikipedia, and while it's not speculative, nor accurate enough, it's a good starting point. the very issue of the cRPG or jRPG is a core issue as to why gamers don't get along across nations, and it's likely just a series of little things that helped shape the industry and the developers interests. i think perhaps there's 2 parts, intransigence, and shared values, what makes us herd animals, sheep.
the market for making and selling games usually sticks with games that sell well, and thus pigeonholes itself into these weird audiences. i.e. east/west that only exist because of the cultural differences. i don't think that many FPS games get released from japan or RPGs from america, because they just don't sell or get the full attention of an audience. i don't blame wolfenstein for creating the FPS, nor FF1 for creating the RPG, simply because its bogus. sure, there's been some crappy FPS and RPG games, and RTS games like starcraft or CnC are universal in some ways, but it's the little things that help sell the games.
With the internet's hype machine though, games like TWEWY or ikaruga get noticed far more than they normally would, and the same goes for final fantasy which is quite remarkably average IMHO, though it is devastatingly long. maybe western RPG's need some fan service to get the vaunted attention of japanese developers to embed english into the game during development. though, that would be very unlikely and ultimately, disastrous, i.e. "all your base are belong to us" springs to mind.
there's also the cultural meme's, i.e. that americans love the idea of constant combat, i think combat just makes a whole lot more sense to casual or competitive gamers because there's tangible short-term victory over the game, and you get that endorphin hit and a sense of achievement, etc. (though, is street fighter 1/2 a western idea ?). The very same thing can be said for RPG's too, the "ding" effects and the tangible rewards in-game, getting SP's to spend on levelling up just by hitting an end boss or end of chapter/level or reaching an FMV cutscene that looks fantastic. Perhaps RPG's are more prevalent because it is a reward for effort or perseverance something that isn't quite as embedded into the american value system.
i don't really believe that's the entire answer, but it's not in me to value or replay the game to get that 100% completed score, (hence my woefully low xbox360 pointscore), but it might go some way to explain why RPG's sell in the millions in japan, while in europe and america, they require so much more effort, hype and speculation,
i.e. i would prefer if there was a game like mass effect released every 3-4 months, it's not going to happen, but theres always hope. (probably end up with kingdom hearts: the high school musical returns. with pirates of the carribean.)