Tenure and Promotion. Again.
When you start a PhD program in the sciences, there are generally two options advisors suggest (or push towards): becoming a professor like them, or working in private industry like a laboratory. Some knowledgeable professors might suggest looking into the government as well, but it's basically be a professor or work in a lab of some kind. This represents dominant thought in Academia for decades. And, on a psychological level, it makes sense: "...this is what I did, and therefore what I know, so you must do it too..." Just for the record, however, there are plenty of jobs outside of Academia and government for a PhD. In fact, only about 10% of PhDs work in Academia, and only about another 20% or so work in government. That said, it's tradition im Academia that, once you get a tenure-track gig, you stay at that location because...well...you need to earn tenure. And I don't use the term "earn" lightly. It takes a LOT, and I've blogged about it previous...