Fame
Have you ever met a famous dive instructor? Didn't think so. SCUBA instructors generally toil along in the background unless something really bizarre happens. For example, how would you like to be a SCUBA instructor who miscounted his divers after they surfaced, and told the dive boat captain to head back to port? Probably tough to get teaching jobs after that one.
However, you might get famous if you teach a celebrity to dive. Let's say you get some glamour shots with a sweet young starlet in a skintight wet suit; or perhaps a beefcake photo with the hottest young stud to hit Hollywood in years. Oh, and you're teaching them to dive, too. You're not sure how you landed this gig, but it will probably be good PR for your career. Unless, of course, something really disastrous occurs. Then you'll still be famous, but not for the right reason.
Of course, you can gain fame and fortune for your diving skills, but it might not result from your instructional talents. Ever heard of Mel Fisher? He used diving to realize his dream, and made out pretty well financially from it.
Fisher undertook a life-changing search for the Atocha, a Spanish galleon carrying tons of gold and silver, plus a nice cache of emeralds. Atocha had sunk off Florida in 1622, and Fisher located the vessel in 1985 after a sixteen-year search involving lots of personal and financial sacrifice. Fisher's loot is probably still being sold piecemeal in some Key West jewelry store.
You've probably also heard of Jacques Cousteau. This legendary French diver, along with Emile Gagnan, invented the demand regulator that allows SCUBA divers to effortlessly breathe underwater. Cousteau also launched numerous dive expeditions designed not only to showcase stunning marine environments, but also to highlight the necessity for marine conservation. That's it for the history lesson, but Cousteau's story is worth a look on its own.