Your assumptions don't account for whether the content being taught is correct or not. Goals and rational actors notwithstanding one of the most relevant metric

Your assumptions don't account for whether the content being taught is correct or not. Goals and rational actors notwithstanding one of the most relevant metrics here is the correctness of the content being taught and that is something the student is not capable of assessing. As a result student demand is no indicator of quality of the content. It may be an indicator of the quality of the learning experience but that should not be conflated with the quality of the content.