My cousin got my grandmother moved to Linux Mint with some actual success. All she did was check her email and browse the internet, and Linux can do that perfectly competently.
minus the cost of supporting windows
minus the cost of malware and virii on windows
hmm, so that works pretty well, IMHO :-P
You can get windows laptops for $100–$500 just get one of those and put Linux on it? Not a single person's grandmother (except maybe that one that plays Skyrim) needs a $1400 laptop, total waste of resources.
Way back in the day, I set up my grandpa with Slackware and FVWM. Yeah, I had to edit a configuration file to add a program - but that also meant that once I set it up, it would never break.