Obviously the dealerships are typically more expensive but that is from marking up parts and labor not from trying to pressure you into buying a new car. If Ford had it the way Apple does brakes would be built in to the transmission, last for 60,000 miles, and be priced at $25,000 to repair.
My specific complaint about my 12 mini is that it needs a new frame, back glass, camera, and battery. $89 dollars is obviously unrealistic for those parts. And, like you say, phones have fewer parts that make up a larger portion of the total cost for the product. Unlike with a car, you can actually swap everything into a new frame pretty easily.