The field of commercial diving can offer a great deal of possibilities to an individual. Commercial divers can find a niche for themselves doing underwater welding, non-destructive testing, photography, and even medical based jobs depending upon the direction the person is interested in exploring.
My advice to anybody interested in the field of commercial diving is to contact one of the better known commercial diving schools and talk to a counselor there. I myself spent a couple days at the Ocean Corp in Houston Texas before deciding that a career as a Scuba Instructor was more along my interest level. A few of the schools you could talk to would be the Ocean Corp, Divers Institute of Technology in Seattle or The College of Oceaneering here in Southern California. They are far better prepared to give you all the information you are seeking. Good luck!