noone1:
Still highly doubt they are building a car. Most likely it is just technology they intend to license. Even if they do build a car, the impact of it will be less material to Apple than even the Apple Watch. They'd pretty much have to buy a manufacturer and even then you'd be looking at only a few million/year install base assuming 100% of the cars you sold were the new product.
More than likely they'd like to license their technology so it could be adopted by millions of cars across all brands. I'm not sure how successful they'll be at this considering everyone and their brother is dumping huge amounts of money and resources into it too and may not want to sell their cars with Apple's technology if theirs will be free and sufficient.
There also remains the possibility that the Apple Car is just a cover story and that they are actually working on something entirely different. While that might seem unlikely, given the specific hires they have made, it is pretty hard to see the business case for what would be a low margin product (relative to their normal margins) at best.
I think Porsche has the best margins in the industry, around 23-24%, if I recall correctly, which is significantly below Apple's current margins, and I don't see how they are going to make up the difference in volume selling cars. Software licensing would be a big departure, and I don't know if they would go this route either.
Clearly, Titan is a big project, but exactly what project it is isn't necessarily so definite as everyone thinks, in my opinion.