So I constantly had to fight management about paying my people when well I moved to IT. Management saw them as replicable by anyone that knew the software we used. I saw them as domain experts that knew HOW we used the software we used, the software was secondary to knowing the company (and basically how every job was done in the manufacture of a 30,000+ part product). When I was a dev, we were partnered with industry domain experts so that we understood how the software was implemented to a level that 'self documenting code' never will.

Software is a cog. You're code can't be that self documenting to become domain expert for the domain it is trying to fill. That's like documenting how to train for a marathon by looking at running shoes.