But he is working on your terms. It's a choice between working at home, without a boss, on anything you like. Or working for someone, on a specific project or piece of code.
Also, I doubt you would pay a guy just getting started learning objective-c $10k/month :)
I pulled in a good amount as a lead designer at a software company (though not 10k/month). You are absolutely right that the success of OneVoice is not enough for even a small company. But for my tiny company it is good.
Also my Objective-c skills are not worth anywhere close to $10k per month. Though someday I'll be a good programmer.
Good for you. Not having to tolerate micromanagers and pointy haired bosses? Priceless. Also the world is not America. $20,000 can feel more like $100,000 in another country. Tons of competent programmers working 12 hour days, 6 days a week, make like 1400 dollars per month (exc insurance) in my country --if they are lucky.