I believe that anyone who works on an iPhone app in their spare time for a year, and who picks a known winner category (GPS tracking, bible app, free book downloader, offline city maps, etc.) can make a living.
Remember - most people who try at everything fail. Right now, the mobile market is red-hot, and it's a good way to make a living. It's got to be the easiest way to sell software and make money, with a much higher success rate than making a website or a Facebook app.
Moreover, you can command ridiculous rates as a contractor right now for iOS expertise - much better than for JavaScript programming on average.