re: Steam. For getting your game on there, there's no Japanese documentation for commercial or doujin devs to work with (Treasure were so confused by it they threw Ikaruga on Greenlight), so almost every game goes through a western publisher like Degica or Nyu Media. What this means is that most will not even bother. If they try they will have to go through the Greenlight process. Valve also doesn't accept games on Greenlight OR any game unless they have a full description in English.
Secondly there's no real PC scene in Japan. When there is, they're buying Razer's garbage, playing CS:GO or TF2 or Half-Life or Portal... they're not interested in their own stuff, they're interested in the western PC gaming world, still a minority though, but Japanese fans of western content are out there.
Another issue is publishers and developers region-locking Steam games so Japanese can't buy them (known as omakuni/おま国), many Japanese games released on Steam are not available in Japan. This is done for a bunch of reasons: either the creators don't want to undermine domestic physical retail sales and physical stores, or they don't want people purchasing cheaper foreign copies (7100-8800 yen vs. $40/50 USD), or the game has no Japanese language support, or there's double DRM involved (Steam games which require Uplay, Origin, etc)... the list goes on. Bamco, Sega, Falcom, Konami, Capcom, EA, Square, all guilty. There's even more that do this, but I know that Bamco, Square and Koei are the mains.
http://kakaku.com/item/K0000879064/ - here's a list of stores offering the GTX 1080, and their prices. Since the majority of stuff is imported into the country, it's ridiculously expensive to build a PC gaming rig domestically, domestic prices are far above the US/Canada. I realize that the 1080 is hardly obtainable even inside the US so maybe it's a poor example, but the cost is always going to be higher. And it isn't as if you're ever going to need a PC to that degree to play 2D games with, but it's just an example of why people opt for a one-off console purchase. ... I don't even think you could make a PC build comparable to the specs of the PS4 in Japan and have comparable prices, and why would anyone do that when they could just buy a domestically-made console with warranty and domestic support? And that's even assuming they know how to build a PC, or get someone to do it for them. Any way you look at it, it's pretty counter-productive.
And even still, if someone wants to buy a doujin game which was released at Comiket, they could just order it from Toranoana or Melonbooks, or buy it in real life. They're either the same price or cheaper, unless the game is physically out of print and hard to find.
Steam is primarily a credit card and PayPal oriented design, neither of which are terribly commonplace in Japanese life (although credit cards are becoming increasingly more popular), bank transfer and convenience store payment have always been the norm, but Degica is also largely responsible for conbini payment becoming available on Steam as well. This didn't happen until sometime in 2014, so the last... 10 years or so, Japanese have had to either use credit cards or PayPal to purchase Steam games on, assuming that a) they're not region-locked and b) they have Japanese language support.
Steamspy isn't accurate either. You're telling me Eschatos has a margin error of 1400... and for Japanese who want to play the shmups on 360? 360 consoles with controllers are already under $50, the games range from $20-50 depending on rarity, some higher than others (Raiden Fighters Aces goes for 13,000+ yen, Daioujou Black Label Extra is also pretty high up there due to only ever having one print).
It's primarily a western platform with terrible support for both Japanese developers who wish to get their content on the platform, and for those wanting to use the platform. Degica at least seems to be making change for the better but I just don't see the platform ever taking off in Japan even if every shmup in existence comes to it. Degica also seems to be going through a transitional period where not even they can guarantee their ports will be as accurate as the 360 releases. There's lots of little things involved which doesn't surprise me that the majority of people purchasing shmups on Steam are westerners.
