The love of the subject is a given. The article states as much. The whole point of the article is that the rewards of an academic life are not presently commens

The love of the subject is a given. The article states as much. The whole point of the article is that the rewards of an academic life are not presently commensurate with the risks and sacrificies it entails. The pay "in a certain field" is irrelevant; the article is about pay and working conditions in academia.