No. Changing one's primary operating system takes time, dedication, and is a lifestyle change, similar to moving somewhere remote. Changing ones AC filter is none of those things.
If you and your grandma only rely on the computer for its web browser, then good for you. You have flexibility that is not afforded to most people. But that's not how a person's phone works; phones dig a lot deeper into one's lifestyle, intentionally so. The walled garden was constructed to keep outsiders out, but now it seems the primary purpose is keeping those inside hostage.
Nobody in my life even notices when they change their 'primary operating system.' They buy a phone based on what looks cool at the time, sometimes it's android, sometimes it's iphone. They move freely between chromebooks, windows, and mac os, because everything is online anyway. It's only 'experts' who have trouble with this.
You make people sound like they are semi-automatons?
If a 15 years old can do so (me) then other people can do so as well. I did not feel uncomfortable at all when i first installed ElementaryOS and then moved to Fedora. everything just works, i never ever had to worry about drivers or stuff like that
My mother-in-law recently became fed up with Windows and asked me to install Linux for her. I gave her Debian with a Mate desktop.
She loves it. Zero problems. It's been a week and she's using it just fine. No lifestyle upheaval.