firefox users are also much more likely to use a search engine other than google too, so more than just the browser is affected. Search is Google's primary money maker so firefox users not using google search would cut into their ad revenue. I would think Google would won't to eliminate firefox, but in doing so they would just prove firefox users' point as far as privacy/openness is concerned.
I had no idea Firefox users are much less likely than others to use Google as search engine. Interesting. How much is much — do you have numbers for it?
EDIT: I'd also like to know whether this is a robust difference, in the sense that someone who has both Firefox and Chrome is more likely to search using Google when running Chrome than when running Firefox. Do you know?