Is there any reason why an iPhone like UI paradigms shouldn't be adopted while designing a desktop application? Let's say you're developing a windows application, can you not use something similar to a Navigation Controller to push and pop views? Tab bars to separate out discrete pieces of functionality? And presenting table views that you can drill down into instead of just lists of information?
One reason I can think of to not use these patterns is usually desktop applications are much more complex and it might take a whole lot more clicks to do this.