Apple Kicks Google's Native YouTube App to the Curb in iOS 6
On the surface, there's a simpler explanation.
"Our license to include the YouTube app in iOS has ended; customers can use YouTube in the Safari browser and Google is working on a new YouTube app to be on the App Store," Apple said a statement.
Google's official statement was equally diplomatic and talked about how the company is "working with Apple to ensure we have the best possible YouTube experience for iOS users." That's all well and great, but it won't be sewn into iOS. The upside to that is Google will be able to deliver updates to end users on a much more frequent basis.
Word on the Web is that iOS 5 devices will not be affected by any of this and will continue to carry YouTube natively.