A lot of people (regardless of age) have a very fuzzy idea (if at all) of what a file or a directory is. They wouldn't know a operating system if it sat on their face.
The only way to get them to use Linux is to switch the system on their computers. And they'll probably manage just fine(after a bit of initial grumpiness), since most interfaces are pretty much the same anyway.
But they're never going to change on their own.