I don't think you are off the track, from what i understand of this market (and maybe i'm completely wrong) , you are right, no one can think about solving his life with one single phone/pad app, and if you have success with one i like to think that even before that you are preparing another one. It would be like being "one single hit song" band or singer, you can get a lot of money but if you want to live you need more than that, and i think software market is harder than music. There's no magic but i can understand that people can risk a lot of work to give a step so they can make a second one and so on. But i think no one can say that if the land lord fires you from his land is a big surprise, you are the servant and have to pay your tithe while he's interested in you.