In retrospect Super Mario All-Stars is one of the only times Nintendo re-released old games in a way that didn't seem like a rip-off in some way. It always feels like they charge too much or release it in place of a new game or they change it in an unwelcome way (lowering difficultly, voices). But Super Mario All-Stars was four games and they updated them but not in a way that mucked around with the gameplay. And they included Lost Levels which for Westerners was like a brand new Mario game. So even you had the other three and didn't feel like getting them again, it was worth owning just for the "new" game.
It's very NOT Nintendo. I tend to think of Nintendo as, unfortunately, a company that tries to get every last cent out of their customers. Throwing a SNES ROM on a disc and charging $30 for it? That's very Nintendo. Releasing each Mario game on the GBA at the same price as a new game, while mucking with the gameplay, while very obviously NOT releasing a new Mario game for the GBA, while marketing SMB2 as "Super Mario Advance" as if it's a new title, is very Nintendo. The original Super Mario All-Stars is actually a tremendous value and that sets it apart. You wonder if Nintendo originally took a bath on it or something and then become super stingy with all re-releases afterwards.
In theory it doesn't make sense to release this on the VC because then only purists would buy the NES originals. But Sega released the arcade versions of Altered Beast and Golden Axe. Why would anyone now buy the inferior Genesis versions of those games? Capcom has released SFII, SFII Turbo, and Super SFII on the VC. Why would anyone buy the original when the later versions are clearly superior? I could see a real hardcore SF nut getting Turbo over Super as the subtleties of those games is different but Turbo pretty much includes all of the original and makes it redundant. But Capcom's and Sega's plan is to get people to buy the old inferior version first and then later release the better one and maybe get them to buy it again. There is no plan to sell the original SFII anymore. That was just to grab early adopters. Therefore Nintendo could very well have released Super Mario All-Stars on the VC with the intention that the original versions are no longer expected to sell and thus had a limited sales life. Meanwhile, perhaps, some people who bought the originals will buy All-Stars as well. I imagine for those older VC games, those that wanted them bought them already. Aside from new Wii owners the original games probably are not big sellers anymore.