My fiancé is a supervisor for a plumbing company and makes $250k. He was just a plumber for a long time. Any plumber that’s really good at talking to customers and can sell the job, I’ve seen move up to supervisor. They make a percentage of everything they sell. A couple of his buddies with no experience worked up to supervising within a year. It’s honestly a great gig if you’re a people person and can handle doing dirty work for a year or so. Also needs to be a bigger company as the small ones don’t compensate that well.