Car makers are working quite hard on putting more connectivity into their vehicles. It's an enormous future market and is still largely undeveloped.
As for the OS, I doubt that Android will be first choice. A system must be extremely rugged and reliable to run in a car. Automotive hardware has temperature, vibration, EMC and lifetime requirements that are not so far from MIL spec. As for the software it needs to be VERY stable. If you want to allow in drive usage, you'll also have to consider usability, the dashboard layout, your existing design philosophy, Interfaces to the engine computer, diagnostics, Navigation, etc.
This is a huge work. Far different from taking some 7inch Android tablet and bolting it on the dashboard.
Given the market size and the requirements, there is enough room for the development of more specialised custom OSes. No doubt there will be some kind of standard at the end. For example check out the CCC, which is working on something like that.
Of course no one will stop you from doing just that - buy a car holder and slap in some 7inch Android tablet or phablet. You'll have full freedom what to install, how to use it and with who to share your data.
Just make sure you don't leave it in the vehicle over night in a Scandinavian winter or during daytime in a hot summer.
As for myself - I don't really want a car that sends my position, driving behaviour and all kind of engine and safety parameters back to the government or whoever else. But then again, I am probably too old to fit in the horde.