The install base of iOS products is about half a billion and a lot of those people are made up of casuals who can become potential gamers. Since the install base is so large Nintendo wouldn't need to price their games at $50-60. They could easily price their games at $9.99 and millions of people would buy them. Not to mention Nintendo would save money on manufacturing costs since it would be 100% digital.
Why is Nintendo so reluctant to go IOS exclusive? They would easily sell more games on IOS devices than on their own Nintendo brand devices. Just about everyone who bought a 3DS/Wii U already own some kind of IOS device.
Casuals will never come back to dedicated consoles, Apple owns that market now. The people who bought the 3DS/2DS only did so because those games aren't on their IOS devices. Trust me people don't want to have to bring two devices with them. They would rather have one device that does it all.
Nintendo is irrelevant when it comes to home consoles. Nobody wants the Wii U. Nintendo needs to drop their pride and go after that IOS market. Nintendo would dominate like they did back in the day if they went IOS exclusive.