A recent paper in Nature Biotechnology reports that ex-postdocs make lower wages well into their careers, giving up about one-fifth of their earning potential in the first 15 years after finishing their doctorates. The study particularly considered biomedical postdocs, the majority of whom ultimately end up in non-academic careers. This work was also recently featured in Science.
Of note, the new study does not capture nonmonetary priorities postdocs may have. Thinking back to my two postdocs, there were certainly thrilling moments. At all rungs on the academic ladder, scientists have some amount of creative freedom, control over their time and intellectual agenda. However, the constraints on this freedom must be noted as well. At the postdoctoral level, these are largely imposed by a postdoctoral adviser. In faculty positions, they follow from the pursuit of tenure, publication, and of course grant funding.