Safari users can switch between Google, Bing and Yahoo when deciding which search engine to use in Safari on iOS. However, it is debatable as to whether anyone does actually does it.
Rarely anyone does that.
That is why being the default search option on iOS is very important. If you are the default search engine, then there are chances are you will be getting the vast majority of hits from users. Right now, that default choice is Google. If Macquarie analyst Ben Schachter is to be believed, Google pays huge amount of money to Apple for this privilege.
According to Shachter, Google pays Apple $1 billion to be the default search option in Safari across a range of devices.
In return for that outlay, Shachter believes that Google sees around $1.3 billion in revenues, which considering the outlay may not seem much. As is often the case with Google though, things are not as simple as one thinks. The money is welcomed but it is the data that Google can collect on all those extra users that is the most valuable part of this transaction, and one which Google will not want to see go away.
Apple, for its part, probably does not want to have to rely on the inferior Bing or Yahoo, either.
Source: iDownload Blog