Why are teachers paid so little?

...because they are willing to give up a lot to do it.  Jon Fitch, Vanderbilt MBA, gave up a six figure salary to become a teacher:

The Vanderbilt MBA graduate was leading a team of 20 people toward the end of his 15-year executive marketing career, while managing a $15 million budget and various responsibilities with Move, Inc. 

In October he left that career behind and is now found in the classroom working toward a teaching degree and a master's in political science. He says he hopes to teach high school social studies and political science at the community college level. He is paying for his education with his savings and hopes to be teaching by fall of 2012 at the latest.