I am sticking to my original comment. Google has not made any significant amount of money on Android, but it sure negatively affected Apple's market share in the smartphone market, which could have been much much higher if it weren't for Android. If Eric Schmidt were really a friend, he would not have gone ahead with Android, knowing how much Apple had invested in the iPhone project.
The future is Mobile. Both Google and Apple knew that hence the existence of iOS and Android.
Why should any company jeopardize their future over some fallacy of friendship? Google are bolstering their core business with Android (search, ads & user data) so their entry into mobile is logical.