It can't be nostalgia if these kids have never experienced what a real video game should be.
Granted they are exclusive to Nintendo hardware which given their current diminishing hardware market share will mean less exposure, but it's not as if kids today don't know who Mario/Link/Samus are, only difference is that they know Mario/Link/Samus from the Wii/DS/3DS games instead of NES/SNES/N64 games.
Again, I don't have hard data, but the situation doesn't seem as bad as some may think.
Don't forget who had utilized a touch screen for games properly.
I'm aware the DS/3DS/etc do more than games, but anyone that uses the DS browser and thinks it's good is a liar.