Why on earth is that a relevant market. We don't look at cars as separate software from the hardware. Apples competition is Android and if better apps come out on Android it will win whatever small share the luxury option has.
Maybe we would, if there were only two car manufacturers that also happen to run their own private roads, bridges, mechanics etc. that are also mutually not compatible.
It shouldn’t be. There is no monopoly. There are people that are mad you can’t get blue iMessages from an android and you can’t side load “easily”. That’s it.