Oh I am not doubting their marketshare, BUT you have to understand you can get a free or $20 Android Phone or an $800 Android phone. You can't buy a $20 iPhone. There are more low cost options with Android, I very much doubt that the whole Android market is taken up by the Elite high end, high priced phone users. More-so, it's probably the low cost android phones that most users go with. Not everyone can afford a $200 subsidized phone or an $800 un-subsidized phone. Same with Apple yes but with Apple you don't have as many options, hence why the Android market is bigger. If you get my drift
Also BMW is seen as a luxury and performance vehicle, with a certain image they want to portray, Apple also has a certain image they want to portray, Android phones are mostly made of plastic, dull and un-inspiring, iPhones are made of aluminum and glass, again more refined, classier, sexy even. They scream "this is the future" in their aesthetic designs. Maybe BMW thinks it fits in better with their overall image...I don't know.
But it is something to think about...I do think that they may want to concentrate on both markets to be fair and make sure everyone is taken care of. But they are a business first. It's up to them to decide what they want to spend their money on, or not...in this case.