Benedict Evans wonders how many people really care that Android is open:
It's clear that there's a highly vocal and highly technical group of people who love all of the technical things you can do with Android phones that you can't do on iOS, consciously reject the iPhone and care deeply about 'openness' and all the things that go with it. However, it's also clear that these people are a minority of actual Android users, given that the typical use levels seen from Android in totality are lower than those from the iPhone (often much lower).
This seems right. In my experience, my family and friends with Android phones have absolutely no clue (nor do they care) that their phone's OS is "open". It seems that the people who do know and care choose Android for philosophical, pseudo-political reasons, mostly out of spite for Apple.