These people would do well in a lot of high-paying professions. It is also not a coincidence that the lack of good teachers is most severe in math and sciences. Even if they may choose to be a teacher out of personal desire to make positive change for a few years, most cannot stand seeing their classmates, who are sometimes less capable, earn twice or even thrice their income for decades.

In the society we live in, it is important to pay people what they are worth. Would you personally choose this noble path if it means a 50 or 60% permanent reduction of your income and an almost zero possibility of hitting it rich?