To become an academic researcher is to make an enormous upfront investment in human capital, often remaining in school until someone’s late 20s, even early 30s. These are people who often have a relatively high opportunity cost of time, even early in their careers, and they do this while also staring down the possibility of technical obsolescence within a decade of graduation. An academic, if they make a major contribution, often knows it will happen before they turn 40 (30 if they’re a mathematician). This is not a trivial endeavor or decision.
Building a critical mass of high quality employees when such high opportunity costs underlie the requisite labor pool presents a financial challenge. In the face of these costs, as much as half of academic compensation takes the form of non-pencuniary benefits (lifestyle, freedom, flexibility, status, etc). And there’s one more problem, and it might be the biggest. For those in more technical fields, the full career’s worth of (discounted) wages would have to be collected in their first 8 years on the job. To put it another way,for the academic labor market to clear absent these non-pecuniary benefits, salaries would have to double or more.