I don't think those would ever make it into Steam. Valve's put their foot down on games that tried to get Greenlit with that sort of content in the past.
It's more than just that.
Japanese studios and developers generally loathe making games for PCs. You'll quickly realize that most of their PC offerings consists of mainly visual novels, eroge, quiz games or MMORPGs only, with the last one being considerably rare.
Consoles and handheld consoles are what the Japanese clearly favor developing for, and it does not appear to be changing. They even shunned smartphone gaming in favor of handheld console gaming; only a handful of old titles made it to iOS and Android, and even the Playstation phone ended up flopping so much that Sony abandoned the initiative. Look at the sheer amount of console-exclusive titles produced by Japanese studios.
Not that I'm really too concerned anyway; I'm a Sony and Nintendo console owner. The more JP game exclusives on the consoles, the better for me (but not for my wallet).
Off-topic: note to self, never ever play BlazBlue on the PSP ever again; it's a button killer.