"As it stands today a Chrome user is no more valuable to Google than an IE user (well, apart from google being default search provider)"
I'm not sure your caveat is needed -- on a new installation the first thing Chrome does is ask you what search provider you want to use, you're just as free to pick Bing as Google.
Chrome does this, but IE does not. That alone means that a much higher proportion of Chrome users will use Google than IE users. Then factor in the relative name recognition for the two search engines...
I'm not sure your caveat is needed -- on a new installation the first thing Chrome does is ask you what search provider you want to use, you're just as free to pick Bing as Google.