So why exactly is the OS layer becoming irrelevant? Is this that idea that everything in technology will henceforth occur in a Web Browser ... perhaps in some HTML4 compatibility mode?
The OS will become extinct once everything happens in the web browser, and the OS becomes not much more than a web browser itself. And then they'll have pretty much reimplemented Plan 9.
First open apis vary greatly from one service provider to another - and this differs _vastly_ from the plan9 idea of unificating everything as a file. And do you really expect google apps to communicate with their microsoft counterparts ?
Second, I could hardly describe the web as having a unified user experience.
Third, and this is the most important thing, is that you're describing a closed system. What if I want to make something my service provider didn't think of ?