You badly overestimate both the ability and interest of average people in learning to administrate their computers. They just want to get shit done and go do something else. Computers are a tool at best, and more often a super-annoying thing they have to deal with but hate every second of it.

If they actually like any of the computers around them, it's probably the most locked-down ones: their phones and video game consoles.

[EDIT] That is, you're way off in thinking it's only a bunch of soon-to-be-dead grandmas who have trouble operating computers that don't prevent them from fucking things up too badly. The "digital native" generations are barely better.