Generally speaking, those who are qualified to teach and train nurses can make more money by actually working as nurses.
.. Academics describe the nursing workforce as “countercyclical,” meaning that nurses tend to enter the labor market when the overall economy is doing poorly, and to leave the market when the economy is better. One reason for that pattern, according to the authors of the N.E.J.M. article, is that the nursing workforce consists overwhelmingly of married women. Registered nurses “who were not working or were working part-time may rejoin the workforce or change to full-time status to bolster their household’s economic security,” they write.