If they made a Zelda game for iOS for $9.99, then I'd buy it.
Why would they sell something for $9.99 when they could sell it for $300?
What about secondary markets. Not everyone has an iPhone. Some kids are just getting game boy advances. It's going to take a while for Nintendo's brand to die off, and they have time to wow us with great games.
Fools like me will give them money for a chance to reconnect with my childhood.