You do realize there are several SoC's in modern cars right? There's the ABS and stability systems, torque vectoring systems, lane keeping/driving automation, the infotainment system, and more. Sure they're not made to the 5nm level at the moment, but supply chain wise a 15nm part is about the same as a 5nm part when it comes to making the silicon. This is especially true when you're needing them to be more resilient temperature-wise and have other restrictions needed in the automotive space.
I drive a 2017 Santa Fe. Its a pretty basic car tech-wise compared to many others on the market these days. There's still the computerized ABS and traction control system taking samples thousands of times a second and making split second decisions on how to handle the car. There are radar sensors tracking the distance to vehicles around me, that data is being fed to computer systems for automatic cruise control and alert aids. The car features lane keeping features which is based off computer vision systems to track the lines on the road. The transmission system is computerized, being more like a computer controlled manual transmission rather than a traditional automatic. The infotainment system is obviously driven by some kind of computer and contains WiFi, LTE, Bluetooth, GNSS, satellite, AM, FM, and digital FM radio systems along with cameras and radar sensors.
I'm sure I'm forgetting some additional computerized systems on this list. So honestly there are several iPhones worth of computer systems on this list, all with more extreme hardening requirements to expect a longer deployed lifetime than an iPhone and all of which need to reliably talk to each other in some kind of fashion.
Car infotainment systems run ARM SoCs, much like an iPhone.
To compare the complexity of a car and a phone (any modern phone - they're all fundamentally similar inside) belies immense ignorance of both.
Phones are functionally complex, but physically quite simple. The complexity is dealt with by the chip fab and software. Electronic manufacturing processes are basically the same for every device, and so are very well understood and optimised.
A phone is a model of system abstraction. The incredible complexity of the processor and digital logic is abstracted into little black boxes which are then soldered to a PCB. The assembly is then a straightforward sandwich of all the bits.
I don't think anyone's arguing that phones are not complex, but that cars have an order of magnitude more bits to assemble, and that means manufacturing complexity that the existing manufacturers obtained through decades of iteration.
Tesla's a great example - they completely underestimated the complexity of manufacturing (building the machine to make the machine), spent billions of dollars on it and are still struggling with poor fit and finish.
Of course, any company can put the processes in place to build a modern car - it will just take time. To argue that a phone requires as many assembly processes as a car is simply ludicrous.
I drive a 2017 Santa Fe. Its a pretty basic car tech-wise compared to many others on the market these days. There's still the computerized ABS and traction control system taking samples thousands of times a second and making split second decisions on how to handle the car. There are radar sensors tracking the distance to vehicles around me, that data is being fed to computer systems for automatic cruise control and alert aids. The car features lane keeping features which is based off computer vision systems to track the lines on the road. The transmission system is computerized, being more like a computer controlled manual transmission rather than a traditional automatic. The infotainment system is obviously driven by some kind of computer and contains WiFi, LTE, Bluetooth, GNSS, satellite, AM, FM, and digital FM radio systems along with cameras and radar sensors.
I'm sure I'm forgetting some additional computerized systems on this list. So honestly there are several iPhones worth of computer systems on this list, all with more extreme hardening requirements to expect a longer deployed lifetime than an iPhone and all of which need to reliably talk to each other in some kind of fashion.