I don't think they stress over the the APIs and standardized protocol stuff, its much more consuming tuning the system to provide optimal performance than it is

I don't think they stress over the the APIs and standardized protocol stuff, its much more consuming tuning the system to provide optimal performance than it is to swap out a computer. A modern car now has tons of sensors and it takes a lot of testing and fine tuning to get every last bit of performance out at the 'ring.