My father, a farmer type born in 1935, managed to use it easily enough when shown how.
It was typical enough of the tools of the time.
34 years ago the average person did not own a computer. What was computer ownership at in 1990, 10%? The people who owned computers tended to be wealthy, smart or hobbyists which isn't exactly indicative of the average person.
So, your father, who has has somebody who can walk him through it can figure it out. Well guess what, the average person doesn't have a technologically knowledgeable child to show it to them.
Perhaps you have a literate child that might explain context.