There's also the idea on the other side of the coin - whereby experts on a topic underestimate how much they know about it compared to the average person.
And of course there's a relevant xkcd: https://xkcd.com/2501/
Imo it would be more accurate to say that topic experts overestimate how much the average person knows about it.
Imo it would be more accurate to say that topic experts overestimate how much the average person knows about it.