I know an Instructor who pretty much gives dive Instruction away for cost. He does thhis just because he loves to dive. He also has a second job, owns his own gear, owns the gear for students, goes to a shop that gives free air fills, and basically has very minimal personal expenses. He still has to charge a little more than what the class costs him directly and work another job on top of that.
You see, UP got it right, it all boils down to one thing. There's this stuff that seems to be fairly important. This stuff is the real reason that everything costs anything at all if you really stop to think about it. Yep, this stuff is the real driver behind the economy if you take it down to the most basic level. What is this all important stuff? Food! no matter what you do with your time or how much you enjoy what you are doing, you have to eat. The dive instructor has to pay for all the services that other people give him. Why? I mean if the roofer loves putting roofs up so much, why does he charge? Because he has to pay for everything. If everyone could eat free and live for free, we could probably have a good chance of getting this off the ground, however, that can't happen with today's world.
I once read an idea in a Science Fiction book. Molecular Synthesizers(sp?). Little balls of energy that can change the air into any material that you want in any shape. Food, house, car, whetever you want in a floaty, glowing ball. Unless one of you have the design for one of these handy to give to the entire world, NOTHING IS FREE. There are costs for everything, because you are paying all the people who worked to bring you that thing to eat.
