They don't want to kill it because of its search methods or some desire to filter "bad windows content"...they want it or want it dead (either way) to give them a better shot at being your first step into the net.
How many here have google set as home page or within one very short click of home (I use my own home page...google included at the top.
And on my windows pcs its ever worse...I have my home page as home >and< use the google toolbar on IE.
They don't want to share entry points to the net. MS wants to own them.