This is a privileged stemlord who's convinced they're the smartest person they've ever met. It's hard to understand, I know, but they'll never get it

Disagree. In some fields you need many years of theoretical fundation to even begin to understand the bases of what you are supposed to do.

A mechanical engineer will not be able to understand their job without being able to solve partial differential equations, and that is something you learn more efficiently from a calculus lecture at university, not on the job with a master of the trade.