With smartphones, Apple had Blackberry as their competition. But with cars, Apple has Tesla. Completely different.
There already exist a smorgasbord of luxury cars that are social signallers; Apple will have to do something much more 'revolutionary' than they did with the iPhone. There weren't any smartphone equivalents of Mercedes-Benz, Porsche[1] or Maserati.
1. If you're thinking "all of those are petrol guzzlers", you're wrong - Porsche is working on an electric car: http://www.porsche.com/microsite/mission-e/international.asp...
Apple is also more well-known than Tesla currently. I still think it won't be easy for Apple but I've learned to appreciate the power of market perception.