interesting results from StatCounter. Apple have chipped away at Google in some forms of search by introducing Maps and pushing Siri, but overall Google remain as dominant as ever in web search.
The one thing which would make a huge difference- if Apple changed the default search provider in iOS and OS X. But the key here is that Google pay Apple for this position and any switch would be hit users. If Yahoo or Bing got their act together and provided a noticeably better service, then I think Apple would have no problem in switching. But right now moving away from Google would make a user's experience on an Apple device worse. That's why Apple have not moved- not any sense of loyalty to Google.
[Article link via Daring Fireball]