Probably because the regular boring car stuff is not even made by car companies anymore LMAO. The steering racks are made by Bosch or maybe ZF. Brakes come from Brembo. ABS module and its software is Bosch aswell. same goes for brakebooster, EPS pumps, AC compressors, and airbag controllers. I think the only electronics Tesla develops and manufactures are EV power electronics, infotainment, ADAS&Co and the drive motors.