It's on the Super NES, Nintendo 64, GameCube, Game Boy Advance, DS, and in arcades.
It's not on the NES, Game Boy, Game Boy Color, and Virtual Boy. Oh, and that Pocket Pikachu thing. And Game & Watches.
6/12 counts as all? It's just as close to none as all.
Though it was first on the Super NES, so the idea wasn't conceived of yet before that, so that explains the absence on the G&Ws and the NES and it probably wouldn't have looked good on the Game Boy. Similarly, it probably wouldn't have looked good on the GBC, which they didn't have many games for anyway. And the Virtual Boy? Pfff. And the Pocket Pikachu thing? An even bigger "pfff".
I think by saying "every one of Nintendo's platforms" what is meant is every console since the Super NES, and only the more recent handhelds.
So is it really any surprise that a Revolution version is on its way? Even if it was still seemingly a 50/50 chance it wouldn't be a surprise if it did show up.