[notahacker]

Construction, mining and oil extraction firms make plenty of use of people with geology and engineering degrees, particularly in jobs that involve doing research and calculations.

Seems fairly obvious why three years of sitting in classrooms and libraries isn't seen as a particularly useful way of demonstrating aptitude for operating heavy machinery.

[fallingknife]

And yet somehow it is for art and music?

[notahacker]

The practice of art and music is much more conducive to a classroom setting and peer group experimentation & discussion than the practice of operating mining equipment, yes. Though a degree has never been a requirement for being a practitioner in those fields, and much of the study focuses on the theory. Universities also welcome many people interested in studying the theory of heavy machinery, and award them engineering degrees.