some good points, though the cost of internet in-car is the major factor for me- i still do not enable the internet on my phones..(it would occasionally be nice, but not $30/mo. nice).
Companies like Pioneer and Alpine are coming around with Pandora interfaces when tethered to an iPhone. I don't know if they work with Android yet.
Ford and MS are getting there with Sync, and Audi is the first manufacturer offering 3g powered google maps straight from the factory. Of course, it's the 80k+ A8, and only comes with one year of service.
Internet is slowly replacing our ancient media distribution like TV and radio. It's only a matter of time before all cars start rolling out the door with 3g/4g radios in them. But not everyone can or will want to buy a new car. I think the market for internet enabled auto gear is pretty big.
Hopefully, someone realizes this and makes the right products, but we shouldn't hold our breath.