The Census Bureau reports that entry-level employees in STEM fields make, on average, 37% more than their counterparts in the arts, humanities and social science professions. This demonstrates the value of a STEM education. Moreover, those who hold STEM degrees earn more than their co-workers who hold a degree in another discipline.
STEM careers pay more because they are considered more prestigious. Doctors, scientists and engineers do complex, critically important work and they spend decades of their life learning how to do it. This brings them the respect of their peers and the high income they deserve.