The whole thing about Apple's existing customers embracing an Apple car, is that it simply doesn't follow.
It's one thing to be a fan (and customer) of a premium consumer electronics brand, it's quite another to be a fan of a car company.
There are many Lamborghini/Ferrari and perhaps even Tesla fans. Very few of them actually own the cars however, as a car is a much larger investment than a phone or laptop and a premium car is even more again.
At the end of the day, Apple makes its money by being a premium brand with a widespread following i.e achieving high profit margins through sale of expensive products, over a large base of customers.
This isn't sustainable when the price of those expensive goods goes from a few thousand dollars at most, to tens of thousands of dollars. The reduction in the total addressable market alone is probably 10x if not 100x.