Anecdotally, plumbers charge more per hour in some cases than many lawyers make. Their income, however, is limited by their ability to book many jobs and actually carry them out. The opportunity cost of one job is exactly another job. So comparing to other wage earners their income is high, but compared to a banker that can make several loans in the course of a day where the opportunity cost is only capital (which they have practically unlimited access to being that theyre a banker) changes the situation quite drastically.