I know quite a few that have done just fine in this industry, I know 3 people of the top of my head who you'd put in millionaires bracket, yes there those that would be better off working for min wage, but carpet cleaning is the same as any other business, its a matter of getting the work in, and striking a balance with pricing that gives you what you want in the way of reward. Not easy thats why everyones not doing it, those that can do it, often seem to be able to do it in any field as well.
One thing is most people charge to little whats too little that depend on the person, but if they don't think or find they are making enough for them then its too little, and how to charge more is the problem.