good read imo http://bit.ly/3X2Gon
Yup. There's not a lot of money to be had for the independent developer. The general idea is that if you came make an application to support another application you've got reason to put money into it. For example, a companion app for the iPhone. Think Remember the Milk or Things. You have a desktop app or web app that pays for the development of the mobile version. You can recoup costs over a longer period of time but for the casual 1 person shop, it's very difficult to live on. So much competition and so many choices. You need to be unique, make a name for yourself, or just get lucky.
A lot of us would love to believe we could make an amazing application and get rich from it. But sadly it doesn't happen that way.