Good point poster. There's originality on both the western and Japanese side of gaming. Japan obviously controls the console industry and originality is obviously present there with Nintendo. But gaming is the opposite, relying on titles like Mario and Zelda, which are still great but hardly original after 20 years. The US, UK etc has a much broader range of games and really launched some categories: Doom, Goldeneye, Fallout series, various strategys. Same goes for movies. I don't see too many Pulp Fictions coming from Japan and horror in hollywood is violent rather than the more creative psychological.

US popular culture owns in Japan though, especially in music. Today's Japanese pop and rock music is garbage compared to the US.

You could write a thesis on it all but there's originality coming out of both sides.

PS: I'd hardly call Idol Master original. It's just a Japanese nerd's game based off western entertainment, with the sexualisation of young girls added in, something that Japan's becoming known for.