I think Ubuntu and some other Linux distros are arguably more idiot proof than Windows, especially if used by a child with no former experience with anything. The issue of course, is that people just expect every piece of software to work out of the box, and much software that gets advertised to people, including games, targets Windows. Yes, most stuff works with compatibility layers now and more software is targeting Linux as well. However as soon as a person encounters a piece of software where something doesn't just work they will probably ditch the OS, not look for fixes or an alternative, especially for something like a game where there is FOMO attached.