Okay, what about them? These are fields of endeavour that I wouldn't be surprised to see specialized highly talented staff for at a large software company, sure. But, for a small start-up or a self-published developer, many or all of these things can be "muddled through" in a perfunctory way, maybe reincorporating some feedback from customers if the result is really terrible, but ultimately just leaving it up to the market to decide the fate of the product. To me this is basically just the fusion of agile approaches with the entrepreneurial tradition.
I would go so far as to propose that the majority of $1 App Store apps were built by some programmer who pressed the build button in Xcode by hand and never heard of "business modelling".