"Value" is subjective - you or I might value a type of knowledge differently from the way the market does.
However, to the extent that a student is pursuing an education as a means to achieve employment and income, the value of a piece of knowledge to the student _is_ its value to the market.
However, to the extent that a student is pursuing an education as a means to achieve employment and income, the value of a piece of knowledge to the student _is_ its value to the market.