[mandevil]

It was (at least when I looked at this circa 2012, it might have changed since then) largely an artifact of Boeing and Intel: both produced fantastically expensive physical items from factories that were highly sought at by the rest of the world and had amazing profit margins. But were just two companies (vulnerable to management mistakes) and both didn't employ that many people to actually make their stuff. E.g. in 1953 steel alone in the US employed 650,000 people, and now Intel and Boeing combined employ 250,000 people worldwide, the vast majority of whom are engineers/back office types, not actually working on the factory floor.