What makes you think CutiePi Shell will be maintained that long? Android has withstood the test of time, and although you'd need a custom mod to update your Nexus 7, chances are CutiePi won't live that long.
You don't need it to be maintained that long - you just need there to still be some support for Raspberry Pi's in Linux. E.g. I don't see a reason you couldn't run straight Raspbian on it.
