Google is also stabbed on its back by Android OEMs and carriers for replacing many Google services with 3rd-party alternatives. This is especially true in China (2nd largest market for Apple) where almost all Google apps have been replaced/eliminated by local Android brands due to censorship and blocking.
Economically the whole Android strategy doesn't make any sense to Google. From a user's perspective it would be much better if Google provides the backend service coupled with Apple's portable devices. Now we end up in this frustrating market with two options: 1) good services + mediocre devices, and 2) mediocre services + good devices.
Google has two big clear goals with their Android strategy:
(1) keep it's main product (Search) from being locked out (by MS/Apple/Facebook), set aside (made nondefault) or emasculated (ad blockers eventually). This is the main point of Chrome as well as G+ to some extent.
(2) minimize frictions that reduce searches. In the case of Android they give away the OS because if the OS costs more the phone costs more and fewer people switch to an internet phone. For Chrome the push for speed attacks the problem at a different angle - faster internet = happier customer = more searches per person.
There are other benefits and goals Google has with this -- yes they want to boost G+, yes they want to keep the data flowing and building, yes they have grand plans down the road -- but those are all secondary.
Economically the whole Android strategy doesn't make any sense to Google. From a user's perspective it would be much better if Google provides the backend service coupled with Apple's portable devices. Now we end up in this frustrating market with two options: 1) good services + mediocre devices, and 2) mediocre services + good devices.