Before we go any further into your argument, because you're really just stating what almost everyone already knows, let's look at the two games in question.
Inazuma Eleven: Soccer RPG
Sigma Harmonics: Developed by the team that brought Final Fantasy VII: Dirge of Cerebus
I'm not sure what kind of market there is for a Soccer RPG. Honestly, I don't think anyone does. It just seems like two things that shouldn't be put together, really.
Then there's Sigma Harmonics. It's an RPG by Square Enix released in the wake of Dragon Warrior V. If nothing else, it seems like it's the victim of the publisher's own success here. We can play the FFVII: DoC card, too, but that's kind of understood.
Moreover, let's not beat around the bush here. The DS has an incredibly high piracy rate in Asian countries. The Wii, well, it's harder to pirate on.
But you're right about the install base not equaling automatic sales. But I think it's more than that, really. There's tons of deserving games that just don't catch fire the way they likely should. Prince of Persia: The Sands of Time, Beyond Good & Evil, Okami, No More Heroes, Soul Bubbles... there's tons of games that should sell but don't. There's always some intangible element.
Then there are games that shouldn't sell well but do. It happens all the time and all you have to do is peer through the Playstation's Greatest Hits releases, Nintendo's Player's Choice titles or Xbox's Platinum Hits. You'll see tons of undeserving games that sold like or better than gangbusters.
That's kind of the law of averages, though, isn't it? Perhaps there's a bell curve going on. Something's in the air. Whatever it is, having a great game just isn't enough. Word-of-mouth could do well for both games, yet. Perhaps there'll be a lull where people are bored before, say, Valkyrie Profile DS comes out. And, boom, they pick up Sigma Harmonics to kill that time.
I get the point you were trying to make. It's just a rather lame way of going about it.
For developers and publishers, it makes sense to go to the highest install base with the lower development costs. Right now, that'd be the Wii and DS. Conversely, though, there's a market to be had for those people who don't, for whatever reason, already own a Wii or DS. That market, if you're a multiplatform console developer, just happens to be slightly bigger than the Wii's install base. As for the PSP, the releases are so few and far between, it seems, that it'd be easy to be the best game out in any given month. So, yeah, you'll likely get good press and good word-of-mouth between PSP owners.