They can try. Might be successful for awhile. Coaching jobs are generally one season contracts in high school that don't pay well for the coaching part of the job. They make their money doing other things either other jobs for the school system or outside employment. A friend of mine who was the head coach maybe ten years ago got $1800 for the season to be the coach. He moved away to take a job as a athletic director, coach, and teacher after a couple years. Until then, thank god he was married to a doctor or he would have been in the poor house.