"Your granny only uses Linux because you, the geek, set it up for her."
(In my case, both me grans are gone, alas .... but I do have a 95 year old Great Aunt, am I allowed to substitute her? Ta in advance.)
Correct. She used to use Windows, after I set it up for her. Think about that for a minute.
I got calls from her for support two or three times a month. I got calls a couple times per WEEK before I went in and updated all the device drivers that Dell provided with the box, and generally cleaned out all the cruft that Windows seems to accumulate over time.
I tried to interest her in a Mac several years ago, but she hated it, for reasons which she still can't fully articulate (she KNOWS, but doesn't have the TechieEnglish to describe it). When Linux became a viable desktop environment, I dropped off a box with a cut-down Slackware+KDE system, geared exactly to her individual needs. She didn't like it, and I continued to get calls from her to "Fix my Windows, please". Time passed. I continued to help her with windows.
Then something changed. After about 6 weeks of no calls for help, I dropped by to see what was up. It turned out that her sister in Finland had emailed her some pictures & the Windows machine chose that moment to die. Out of desperation, she fired up the Slack box. That was a couple years ago, and she's still using it (she doesn't know it, but it's now Slack 12.2, and will probably stay that way).
Now, instead of seeing her a couple-three times per month to fix her computer, the wife and I make the three hour round-trip drive to visit her a couple-three times per month for tea.
Which would you prefer?
She has also convinced several of her octogenarian+ friends to allow me to "put a better version of Windows" (as they put it) on their machines ...
Now, I'm no fanboi. I have Apple, Microsoft, Sun, HP, IBM, DEC, Tandom and etc. operating systems running within arms reach as I type. Each have their job to do, and they do it as well as can be expected. But I know for a fact that a properly setup Linux system is the best option when it comes to my old Gran^H^Heat Aunt.