Plumbers' riches is an urban myth. When I started out in web development, my billing rate was $325/hour, which a journalist could easily calculate into a $600,000+ year job. In reality, I made around $70k. I suspect the plumbers meme is based on similarly ill-informed calculations. The reality is more humble: $20/hour for hired hands, lots of expenses and unbilled downtime for independents, etc. The average for highest-earning states (NY/CA) is around $60k.