Hold on a second.  Silverlight is a subset of WPF... is it not?

BUILD is going to go down like this (my guess)...

Take Rx C++ AMP WPF and the age of MFC.... It will be a WPF++ for C++ and C# and VB in one box.  It will be very big.  WIN32 will start its long slow end of life, yeilding to a faster smaller codebase.  Think modular windows, don't need win32 compatability it don't load, or may not even be installed on an ARM tablet.