Some trends make me think there will be less cars around in the future. The average age at which people get drivers licenses is rising for example as it is becoming easier to live without them. The car sharing network Car2Go, which one could look at as an early example of how a vast autonomous car network would work, has shown to take 11 cars off the road for each that it adds[1]. Lastly there is a renaissance in many cities right now with planners turning away from car oriented infrastructure, and more strongly focusing on pedestrians, cyclists and public transit. It seems to me that a lot of the car oriented thinking of the 1950s that resulted in the cities we see today is discredited amongst planners and they are trying to move us away from that.
I wonder where Apple believes the car market share is going. Even if automobiles aren't a growth industry they may think it's worthwhile to them to try to take a good share of the luxury market.
[1] http://www.citylab.com/commute/2016/07/car2go-car-ownership-...