It all depends on how hard a person is willing to work at his job. Both can be lucrative professions but you have to look at the tasks involved.
Who makes more a plumber or an electrician?
They actually make pretty close to the same money per year. Always wondered why plumbers don't buy better pants !
I believe it depends on two primary things one: Location: Urban area, big city, etc.; two: The individual. One may handle his business very fairly and professionally while another is sloppy and overpriced.