You clearly don't know many Japanese people. They aren't exactly known for preserving their content. As you said, it's a Japanese game for the Japanese market so "anyone in the world" isn't a huge stretch. It is highly unlikely that anyone specifically saved the installer. It's possible it's lurking, forgotten on an old hard drive, but specifically saved and archived? Unlikely. I've been talking with @biggestsonicfan about this elsewhere and we're going to try to ask our (admittedly medium sized) Japanese audience if anyone has a copy.
I don't mean preservation on purpose, and my example of an old computer laying around in no way implied that. I didn't even mention the word preservation at all. I'm talking about the same reasons that people keep old console hardware around, which Japan has a great used market for. It is highly common anywhere in the world for people to keep old PC hardware around if they have attachment to it, and a lot of people won't actively delete things unless they have a reason to. I stand by my previous statement. But as I already stated, finding people in that scenario would be difficult. It would be difficult even in English speaking communities for something similar released in the west, because the people who would have played an MMO 20 years ago are going to have lives now and not be floating around internet gaming communities.
I'm going to have to go ahead and say that the servers not existing any more is a reason... Anyway, let's get back on track here. A blog post has gone up about the reverse engineering work that's gone into restoring functionality to the game!
Do you mind asking this audience about "Senjou no Valkyria Duel" as well? It's in the same boat as Splash Golf, but is obviously more recent (started in 2012).
Part 2 of the Splash Golf analysis has been published! They are working to get his out very fast it seems.
