Frank Kogan

Yes, my original comment was pointing out not that there wasn't writing about such kinds of music, but that it was all in, as petronia says, the genre ghetto, and thus ignored by non-genre-fans as a legitimate pool to of music to examine, much less as candidates to join the music popularity politics pool. (which I will refer to as "geeks" hereafter.)
The only true crossover has been in the meme arena, (Whatcha Say, Live Your Life) which does not necessarily have ties to genre.

Here's a sample of the kind of writing that is going on within the genre-music niche:
http://blog.animeinstrumentality.net/
http://www.squareenixmusic.com/reviews.shtml
http://randomc.net/category/soundtrack/
http://www.rpgamers.net/reviews/music
http://chezapocalypse.com/episodes/music-movies-shorty-the-music-of-persona-3/
http://animeworld.com/morereviews/macrossplusost.html
http://www.animevice.com/news/top-5-greatest-anime-soundtracks/6653/
http://consequenceofsound.net/2013/09/top-10-video-game-scores-and-soundtracks/
http://otakurevolution.com/content/otaku-revolutions-top-15-anime-soundtracks
http://kotaku.com/5968289/the-best-video-game-music-of-2012

I will, however, note a difference between the actual soundtrack songs and a show/games' associate pop song themes, the latter of which are what you've probably interacted with. (that Faye Wong song, and Utada Hikaru's claim to fame in the west is her Final Fantasy theme)
Even Kpop has some anime themes under their belts, which illustrates how sometimes these songs are written completely independently of the soundtrack production and source material content, although the good shows/games will use their OPs, EDs, and insert songs as motifs.

In that the licensed theme songs are the arena where fandom music interacts with the pop market, it should be noted that anime and VG geeks, despite having heard hundreds of themes, rarely actually venture out into the Jpop market beyond their fandom music bubble. As one of the geeks who has become more invested in the music realm than the shows and games, I often feel a little empty when attending conventions because they don't offer many events "for me," due to that. There aren't any spaces to discuss greater music contexts and analysis, much less meeting people with knowledge of the industry, so as to discuss popularity politics and the careers of artists, as opposed to just their one work that was a show/game theme.
Part of this is that such writings are more focussed on the combination of music and visuals that are specific to the show and its relation to the source material's content. (On the other hand, this has the potential to beget discussion on music inextricable from an audio-visual experience even deeper than most attempts that talk about regular music videos.)
http://www.glassreflection.net/anime-video-reviews/top-50-anime-openings/
http://www.jesuotaku.com/specials/top-20-anime-theme-songs-of-2012/
http://www.jesuotaku.com/specials/top-20-anime-theme-songs-of-2011/
http://www.jesuotaku.com/specials/top-20-anime-theme-songs-of-2010/

There's also more of a trend towards eschewing analysis in favor of simply urging the reader to just listen to the piece in question, followed by an embed to facilitate: http://kotaku.com/tag/kotakumelodic

This is adopted from the "let's just share this awesome thing we found and do nothing else to avoid sullying the experience" approach most media-covering blogs have, which has also been epitomized in the tumblr reblog structure.