I don't know how you can say that. All of the sample C# code that I saw in the keynote had .NET namespace references, as far as I could tell. Maybe those namespaces weren't technically part of the .NET framework, but as long as you're using C# and can bind data to UI elements using XAML mark-up, who really cares?
They said that they went to great lengths to get WinRT namespaces to match .NET namespaces so that apps wouldn't need too many changes. I'm sure we'll learn a lot more at the WinRT session, but .NET was not mentioned once, only the languages were (C#/VB/XAML). Right now it seems that WinRT is a native wrapper around Win32, almost like an updated MFC.