I think that when you wear glasses for so long people just get used to seeing you wear them and the moment they go people notice straight away. I know from experience having worn glasses since I was 13, I’ve had people ask me the moment I wear contact lenses because I still act like myself
It’s hard to say when it comes to Clark though as he was very careful to not let people see him without his glasses, but in other ways too it is a it is a bit of people expecting seeing what they want to see as Clark’s demeanour changed when he was Superman. Although Lois and Clark’s version of Clark didn’t make him out to be a dork as is the tradition there are still subtle differences to how he acts when in both personas to the point that no one would expect Superman to be Clark
