Google is, at heart, an ad company. As far as I understand it (and I don't pay all that much attention to this kind of thing so feel free to correct me), everything Google does has to eventually, at some point, theoretically, go back to advertisement.<p>What this means is that they don't give a (large) hoot if the eyeballs are looking through Firefox or Chrome (to elaborate a bit, I imagine Google would <i>prefer</i> if the eyeballs came through Chrome, but Firefox eyeballs still pay the rent). So from a purely business standpoint, I suspect the "loss" of promoting Firefox OS is less than the "loss" of not being Firefox's default search engine.<p>Also, competition is, as far as I understand it, to Google, A Good Thing. There are probably lots of reasons for this, at least one of which likely has to do with how the Microsoft antitrust thing went down back in the 90s.