Afaik, Apple starts lots of development projects and a lot of them gets "Steved". If the new product isn't enough better than the competition or won't have enough profit margins... axe.
(Point is, the project might have been doing well and following the plans -- but Apple might have found that the target market niche was too small. Or the margins might have been too low for Apple.)
Premium is very premium in the car industry. It is one thing to find $3000 to buy a laptop. It is expensive for a laptop, but it is in the realm of purchasable by a large chunk of the population.
It is quite another endeavour to find $100K+ to buy a car, no matter how you can rationalise it. The total market size for car at that price is probably in the 6 digits cars worldwide and shrinking in the western world.
That falls quite far from Apple business model and expertise.
(Point is, the project might have been doing well and following the plans -- but Apple might have found that the target market niche was too small. Or the margins might have been too low for Apple.)