Someone who is 75 years old today was 49 years old at the peak of the dotcom craze, and is probably a lot more computer literate than you're giving them credit for. What you're saying might have been true 20 years ago, but it isn't today.

Oh no. Not at all. My mother would say "You moved my facebook" when she could not find Chrome. These people exist.

Yeah, no. Maybe in the circles that we run in here on HN but Linda Q. Senior worked as a paralegal 25 years ago and is still using the email her ISP gave her in 2003. She asks her son to fix the wifi and doesn't update her iPad for months at a time. She just found out about Reddit within the last three years. She gets frustrated and clicks the mouse a bunch of times when a system doesn't respond to her input quickly. She doesn't really grasp the concept of an "operating system", just that the device runs some software.

Changing the OS she uses is like tossing a flashbang grenade at her while she's sitting on the couch.