I have a theory that I haven’t explored yet. My mom is not a computer user. She barely knows how to use one, so she doesn’t have knowledge of the MS Windows or MacOS approach of using computers. I suspect if I gave her a laptop with Ubuntu on it and showed her the ropes of how to use it she’d get along very fine. I think she would be able to navigate the UI and never need more technical knowledge than remembering her computer’s password.
Now, before anyone goes and accuses me of being a bad son for leaving my mom in the technological dark, I just want to say she gets by pretty happily with the iPad I got for her, which has an even more foolproof interface than any traditional desktop OS.