Sorry, Robbie -- I hope I don't think I was misrepresenting you.
I am not talking about replacing the desktop operating system, so much as I am talking about building frameworks for consistent access to services that allow us to build applications across multiple devices. As I mentioned earlier, Apple's iTunes is a great example. Exactly what OS does it depend on? On the client front end, it's a Mac app. What does the iTunes music store run on though? How about CDDB's servers? How about the OS for the iPod? The application depends on all these things. It's a cross-platform app at the very core. My point is that as we build more and more of these apps, we aren't going to want to build them all as one-offs, and someone is eventually going to succeed in building the standardized "operating system" layer functionality that simplifies the process of creating such multi-platform applications.