A computer is a general purpose machine, with capabilities for business, clerical work, arts (graphics, multimedia etc), entertainment (games, web tv, media distrubution) and of course communications.
A car, by now, is just a car. It's 2014, they are a known quantity, and the big change they were to bring, they have brought already.
Plus the key in the era of Mac and IBM PC was that the personal computer was just beginning and exploding from only nerds and large enterprises to billions of people. The personal computer was something genuinely new and disruptive for all kinds of markets, business processes and personal life. An electric car is just an incremental innovation on the car everybody already has.
Now, if it was a flying car, or a self driving car, that would have been more impressive in its possibility for change, but still nothing like a computer in the pre-mass computer era.
The current battery tech is holding the entire world back. The next market revolution will come with new power generation (battery) tech that allows us to not worry about charging things every 5 hours.
I have the same thought as you, what Tesla may accomplish as a company may not be affordable electric vehicles but leaps in battery and power storage.
Isn't a car a general purpose machine in the same sense that a computer is? Cars, at some point, were also "genuinely new and disruptive for all kinds of markets", just like computers were long before the Macintosh. I'd say that the Macintosh was little more than an incremental advance in a particular direction of personal computers, and I'll stick to my point that Tesla is just an electric care in the same sense the Macintosh is just a computer.
