>>10164709As far as PhDs are concerned? As a PhD, you're hired by Consulting Business (CB). CB will get hired by, say, Big Pharma Corporation to improve its performance (read: make more money) in a particular sector or division. You and a team from CB applies some analytical framework to tell Big Pharma Corporation how to improve performance.
So, it's not STEM, per se. And, there are going to be plenty of non-scientists (MBAs, JDs, people straight out of undergrad) working there. But, firms hire STEM PhDs for their pedigree, prestige of the degree, and intellectual capacity. And, in many cases STEM PhDs have specialized knowledge in a sector. Back to our example, when Consulting Business gets hired by Big Pharma Corporation, Consulting Business assembles a team of biology PhDs, chemistry PhDs to work on the project.