This coming from a *man* who would crap on the floor rather than learn something about plumbing.
I suppose mechanical engineering is beneath his dignity as a savant.
It's very simple. Plumbing is fine. So is mechanical engineering. But it's narrow. Step back, there's a bigger picture and it encompasses much more than a single, narrow application.
The garbage man is essential to my existence. The mailman, the plumber, etc. But it also isn't very deep stuff. Neither is racquetball. I play that, but I don't pretend it's intellectually taxing.