While I’m sure that it’s a minority of classes, I think that high achieving kids can make a determination of which classes are valuable to attend. And, even if they misjudge, I don’t think it necessarily reflects a terrible attitude.
As an example, DS had one teacher whose class was dreary, professor just wasn’t a good teacher in the classroom /u. That said, the subject was of tremendous interest to my son, he did a lot of reading, did all the psets, attended office hours, and the teacher and he had a chuckle about how well he performed without attending class. IMO, this is an example of a great teacher, just not a very interesting one during class, and a great working relationship with a student. Sometimes you just have to play the hand you’re dealt.