I think that might just be a vicious cycle. As things currently are, Japanese gaming has been highly focused on consoles, with the PC market left pretty much for dating sims only. Given that the consumers haven't already been in a habit of keeping their PCs in good shape for the more demanding westers shooters/rpgs, the risks in putting out a hardware-demanding, good PC game and hope that consumers would take it up would be too great.
It's not that X-rated games aren't available, it's that major retailers don't have them. Pretty much you have the general gaming stores that don't want anything to do with eroge (at least in their main levels), and then you have some basement store that's dedicated to eroge. (Having seen it personally, they really are dedicated - and only to eroge).One thing that left me wondering about the article was how it said many Western games get a classification similar to adult games (forbidden from under 18 years, I reckon) and thus major retailers don't carry them. Getting that classication in itself is perfectly natural, since having a look at your game shelf reveals games like Witcher, Dragon Age, Fallout, etc are all for adults only. However, for shops not to sell them (or hypothetical similar Japanese games, if nobody buys Western games) because of that is incredibly strange when you also say adults are used to gaming to pass time during long commutes. So, despite gaming a lot, adults in Japan are restricted to games meant for kids? Strange place indeed.
So that kind of leaves our violence-rated games with no takers. I doubt digital content delivery like Steam has much footing there, if at all.