AHH, I see the confusion. I *DID* say that people actually working in the field were the exception. I'm not speaking of them. I'm speaking of "muggles". Doctors, nurses, mechanics, engineers, lawyers, secretaries, etc. People not in the "DP" department.
I was still in Elementary school in the '70s. I knew exactly one family that had a computer and it was a TRS-80. Mostly because the dad was an electronics engineer. My dad used a computer at work (civil engineer) but really didn't know how it worked beyond the programs he used. He also had a scientific calculator in the early '70s. A true rarity at a time when even a 4-banger cost $50 (and that was real money then).
At that time, balancing the check book was generally done un-aided with pencil and paper math. At most, a simple calculator might be involved. Why would anyone in that time feel that they NEEDed a computer to balance the check book? Especially given how much it cost. My friend's dad didn't evenm use their TRS-80 to balance the checkbook, it was too cumbersome for that.
My next-door neighbor was a programmer on a mainframe (COBOL IIRC) but didn't have a computer at home. I imagine he is now one of those 60+ who does have a clue about computers.
My contact with computers beyond the TRS-80 was dialing into the school system's mainframe with a Honeywell terminal as part of a summer program for gifted students. Very occasionally, we used punch cards.
By the '80s when I was in high school, we started getting C64s when the price came down but our parents weren't even vaguely interested in them and had no idea how they worked. I would guess perhaps 10% of the students used and understood computers. Another 20-30% saw them as advanced game consoles.
By the late '80s I had an XT clone with the v20 upgrade. I was building and repairing PCs. The customers were definitly using them by rote and had no idea how they actually worked.