The real problem for me is that support is really hard to come by if something goes wrong. Grandma can't access the internet on her Ubuntu system — who can help her? I'm 500 miles away, my parents are equally as far in the other direction. Neither myself or my parents use Linux as a daily driver either. Her neighbors have Windows or Mac machines. Does she drive to Best Buy with her desktop? Call in external help?
If she uses Mac or Windows machines, help is just a lot closer. My dad can replicate her issues on his machine and walk her through it on the phone, or I can. Her neighbor will at least potentially be familiar with the way the OS looks, so can offer greater help.
I'm not sure how you can close that gap if you're not next door to the individuals who would benefit most from it. While it may be a great individual solution, the support burden just isn't a solved problem in my opinion.