Hell if I know. This thread is based on a claim that people go into nursing and teaching out of altruism, and not for compensation. I'm pretty sure that's not true. Both are well-compensated, safe paths to a comfortable lifestyle and, especially for teaching, to a secure retirement.

No teacher is going to tell you they're not altruistic, and that they're in it for the money. They see themselves as doing good, and I agree that they are. But that's not what drives entrance into those fields.