My impression has been that in the sciences, there are a significant number of people who get into a graduate program, just do what they are told by their advis

My impression has been that in the sciences, there are a significant number of people who get into a graduate program, just do what they are told by their adviser for a few years, get handed a PhD, land a job on the recommendation of their adviser, and spend the rest of their careers elaborating on what they did as a student. This is not necessarily bad, as there is a lot of drudge work that needs doing in science. The problem is the pressure to over-promote everything you do. The reality is that very few people, even among PhD's, have the capacity to do really original work. There was a study many years ago on the physics community that found that less than 10% of physicists published even one thing in their career that someone else found worth citing.