But simply because of the download service, I'm sure 20-30-year-olds who remember the NES (or even those slightly younger who remember the Super NES), if Nintendo can get the word out about it, people will buy it JUST for those old games. At first.
Once they have a Revolution, even if it was meant for the classics, they have the ability to play Revolution games, and will actually take the time to look at the Revolution section in the game/electronics stores.
If someone was satisfied with their Xbox or PS2, they wouldn't need to look at the GameCube section. Sure, it has a lot of exclusive games, not like, say, the Xboxes which nearly all are also available for the PC, but if casual gamers don't feel like they're missing anything, and don't have the ability to play GCN games anyway, why would they look at the GCN section, especially if they're not hearing about it as much?
This retro library is one of the Aces in Nintendo's hand. It's a service that the competition doesn't have. Sure, the others have backwards compatibility but not on this level, and not as convenient. It should sound even better than when DVDs were new and people were buying a PS2 for its DVD-playing ability. Well, ideally, anyway.
So the download service will get it into more homes because of this feature alone, including quite a lot in the hands of older gamers.
I predict that Nintendo will make a big deal about the "virtual console" and heavily at launch - very heavily, perhaps, and they really should. It will be a big point whenever people make comparisons between the three consoles and Nintendo will remind us again and again, especially between major Revolution game releases. They will hold off on releasing some games to maintain interest by putting them out over time. I don't foresee all of their games at once, and even if they do for some nutso reason, perhaps some third-party developers had been sitting on the fence and if it does become successful (which I predict it will) then they'll want a piece of the action, so games might come later anyway.