[scarface74]

If Apple customers are the most affluent and are worth at least $12 billion a year to Google, how much are the statistically less affluent Android users really worth?

How much are customers buying $200 phones worth to advertisers compared to customers paying 3 times as much?

Google also has to pay third party Android OEMs a share of search revenue.

[selectodude]

I would imagine a lot of it is mindshare. Apple is trendy and had already called their bluff once and made Bing the default search engine for a time.

Google pays Apple to make Google the search engine on the iPhone for the same reason that Coca Cola and Anheiseur-Busch spend tens of millions per year on 30 second spots during the Super Bowl.