Right; in fact, we can see pretty easily that just transferring the predictor's probability to our better more precise predictions will intrinsically increase their apparent confidence. The point of our versions is to be narrower and better defined, and so we will judge our prediction correct in fewer states of the world than they would have judged their own prediction (independent of any biases); fewer states of the world means less confidence is justified (P(A&B) <= P(A)).

Of course, in practice, due to the many biases and lack of experience afflicting them, people are usually horribly overconfident and we can see many examples of that in this thread and the past threads. So between the two, we can be pretty sure that predictors are overconfident.