I think in general the Western point and click adventure style is attractive to an audience old enough that the artwork in most visual-novel style games, as well as the emphasis on youthful protagonists, has no drawing power. Look at the most successful portal for Age of Enigma-style adventures in the US, Big Fish Games, and you’ll see a huge audience of 40, 50, 60 somethings play lots of these games (full disclosure: I buy four or five of them a month, mostly for my parents to DL; I’m probably very (too?) old for the B-game genre as it is). Point and click is actually a reasonably large genre of games, but the audience is almost completely separate from, say, the console gamer demographic. The other major impediment, as I see it, is that the conventions of B-games seem rooted in the languages of static art and prose, while the Western adventure tradition has always aspired to a cinematic feel. Even when a point and click adventure game uses comic strip style art, the effect comes across as a series of storyboards rather than a printed feel.
And the porn? Even a title as innocuous as Leisure Suit Larry has a difficult time getting full distribution. For that matter, even the soft-focus, genital-covering sex in Mass Effect and The Witcher got nationwide catcalls from moralist types in the US. B-style plot and visuals will always be underground in the West (save, perhaps, parts of Europe).
It is a good sign that Hanako and Winter Wolves have been able to get greenlit on Steam; in particular, the romance scenes in a game like Loren are an interesting ‘baby step’ towards the types of storytelling b-games are known for. Things take time.