>>4426675most art schools worth their salt prides them selves that the teachers are "active working artists" the theory is that their teaching will be sort of up to date, and founded in real world experience. That means that those kinds of teaching positions are designed to also support an artistic practice, making them quite lucrative for artist.
My uni tutor-- a quite successful painter, had a large studio in new york and everything -- said that the teaching job was not really about the money anymore. The real value was having a finger on the pulse, getting a overview of what young artists were concerned with -- keeping him relevant.