> but interchangeability works like it does for software engineers.

By which you mean, it does not? A lot of harm was done in the industry by trying to make programmers interchangable.

No, by which I mean exactly what I wrote. I even gave an example.

I believe you are working with a different concept than I meant. The concept of these "interchangeable gears" is that a person can walk out of one dev/manager/retail/teaching job and walk into another in a different industry, and be completely effective on day one.

This is a concept I learned from several professors across many classes in 2 separate colleges. I've read it in management blogs too -- it's a widely held incorrect concept.